gamma-linolenic-acid and Body-Weight

Background: Retinoids, which include isotretinoin, reduce sebum levels, the degree of epidermal wetness (CORN) and cause an increase in transepidermal water loss (TEWL). Weight gain has also been observed in isotretinoin-treated patients. An agent that can reduce the severity of isotretinoin side effects is evening primrose oil (Oenothera paradoxa). The purpose of this study was to evaluate the effect of evening primrose oil supplementation in patients with acne vulgaris treated with isotretinoin on skin hydration status (CORN), transepidermal water loss (TEWL), skin oiliness (sebum) and changes in body weight and BMI. Methods: Patients diagnosed with acne were assigned to the isotretinoin-treated group (n = 25) or the isotretinoin and evening primrose oil-treated group (n = 25). The intervention lasted 9 months. CORN (with a corneometer), TEWL (with a tewameter) and sebum (with a sebumeter) were assessed twice, as well as body weight and BMI (Tanita MC-780). Results: The isotretinoin-treated group showed statistically significant reductions in CORN (p = 0.015), TEWL (p = 0.004) and sebum (p < 0.001) after the intervention. In the group treated with isotretinoin and evening primrose oil, TEWL and sebum levels also decreased significantly (p < 0.05), while CORN levels increased from 42.0 ± 9.70 to 50.9 ± 10.4 (p = 0.017). A significant decrease in body weight (p < 0.001) and BMI (p < 0.001) was observed in both groups after 9 months of intervention. Conclusions: During isotretinoin treatment, supplementation with evening primrose oil increased skin hydration. However, there were no differences between groups in transepidermal water loss, skin oiliness, weight loss and BMI.

Topics: Acne Vulgaris; Body Weight; Dietary Supplements; gamma-Linolenic Acid; Humans; Isotretinoin; Linoleic Acids; Oenothera biennis; Plant Oils; Skin; Water

Plant extracts and fungal fermented feed with gamma-linolenic acid-rich microbial oils are perspective additives for use in animal nutrition as appetite and digestion stimulants, stimulants of physiological functions, for the prevention and treatment for certain pathological conditions, and as antioxidants. The activity of antioxidant enzymes and the level of reduced glutathione were measured in the plasma and in liver, heart and kidney mitochondria after 42 days of feeding broiler chickens both regular and combination diets. These were selected based on our previous experience. The administration of agrimony and gamma-linolenic acid resulted in a significant decrease in superoxide dismutase activity in all four bodies in contrast to plant extracts. We conclude that the decrease in activity is due to decreased production, and hence dismutation, of superoxide radicals to peroxides followed by lower activity of glutathione peroxidase, which was not seen in the case of only plant extract administration. Generally, higher glutathione reductase activity would be in response to increased demands on reduced glutathione as a cofactor for the reaction catalysed by glutathione peroxidase and the utilization of glutathione itself. However, measured levels of reduced glutathione showed no change. The results argue against any oxidative stress conditions. The application of agrimony extract appears to be suitable for the antioxidant effect against peroxidation of gamma-linolenic acid. As the efficacy of measuring the effects of diets on the oxidative stability of meat caused by selected antioxidant enzymes is rather low, additional data from the experiment will be processed to clearly assess the influence of this combination of diets.

Topics: Agrimonia; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Antioxidants; Body Weight; Chickens; Diet; Eating; Fermentation; Fungi; gamma-Linolenic Acid; Plant Extracts; Vitis

In nephrotic syndrome, large amounts of plasma proteins are lost in urine, causing a decrease in the plasma oncotic pressure. This leads to enhanced hepatic synthesis of albumin and other proteins, including lipoproteins, causing a secondary hyperlipidemia. Essential fatty acids such as gamma-linolenic acid (GLA) can prevent accumulation of cholesterol in the body, and spirulina has an appreciable amount of GLA. In this study 23 patients (age 2 to 13 years) with nephrotic syndrome received either medication (group I) or medication plus 1 g/day Spirulina (group II). Height, weight, and serum levels of fasting blood sugar, triglycerides, total cholesterol (TC), and low- and high-density cholesterol fractions (LDL-C and HDL-C, respectively) were measured before and after the 2-month study period. Mean height and weight were normal compared with healthy, age-matched Indian children. Lipoprotein cholesterol levels were significantly increased at baseline. TC significantly decreased by 116.33 mg/dl, LDL-C by 94.14 mg/dl, and triglycerides by 67.72 mg/dl in group II; in control group I, these values fell by 69.87, 61.13, and 22.62 mg/dl, respectively. The LDL-C:HDL-C ratio also decreased significantly, by 1.66 in group II and 1.13 in group I. TC:HDL-C decreased by 1.96 in group II and 1.19 in group I. HDL-C:LDL-C also improved significantly in both the groups. It can be concluded that spray-dried Spirulina capsules, rich in antioxidants, GLA, amino acids, and fatty acids, helped reduce the increased levels of lipids in patients with hyperlipidemic nephrotic syndrome.

Topics: Adolescent; Anticholesteremic Agents; Bacterial Proteins; Body Height; Body Weight; Child; Child, Preschool; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Female; gamma-Linolenic Acid; Humans; Hyperlipidemias; Male; Nephrotic Syndrome; Spirulina; Triglycerides

Cats have limited Δ6 desaturase activity. However, γ-linolenate (GLA) feeding may by-pass the Δ6 desaturase step allowing arachidonate (ARA) accumulation via Δ5-desaturation. Alternatively, high dietary linoleate (LNA) may induce limited Δ6 desaturase also resulting in ARA accumulation. Fatty acid profiles were determined after feeding high LNA, high GLA, or adequate LNA diets. Adult female cats (n = 29) were assigned to one of three groups and fed for 8 weeks. Plasma samples were collected at weeks 0, 2, 4 and 8 for plasma triacylglycerol (TAG), total cholesterol (TC), lipoprotein (LP), and plasma and red blood cell membrane phospholipid fatty acid determinations. Time, but no diet, effects were observed for TAG, TC, and LP fractions at weeks 2 and 4 with significant increases likely due to increased dietary fat. However, all values were within feline normal limits. The GLA diet resulted in increased dihomo-γ-linolenic acid (DGLA) and ARA as early as week 2, supporting a ∆5 desaturase. Further evidence of Δ5 desaturase was found at high dietary LNA with the appearance of a novel fatty acid, 20:3 ∆7, 11, 14, apparently formed via ∆5 desaturation and chain elongation of LNA. However, Δ6 desaturase induction at high dietary LNA concentration was not observed. Cats are able to maintain plasma and red blood cell ARA when fed a practical diet containing GLA using what appears to be an active Δ5 desaturase enzyme.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acid; Body Weight; Cats; Dietary Fats, Unsaturated; Fatty Acid Desaturases; Female; gamma-Linolenic Acid; Gas Chromatography-Mass Spectrometry; Linoleic Acid; Lipid Metabolism; Liver

Hypercholesterolemia indirectly increases the risk for myocardial infarction by enhancing the ability of platelets to aggregate. Diets enriched with polyunsaturated fatty acids (PUFAs) have been shown to reduce the detrimental effects of cholesterol on platelet aggregation. This study investigated whether dietary hempseed, a rich source of PUFAs, inhibits platelet aggregation under normal and hypercholesterolemic conditions. Male New Zealand white rabbits were fed one of 6 dietary interventions: regular control diet (RG); control diet + 10% hempseed (HP); control diet + 10% partially delipidated hempseed (DHP); control diet + 0.5% cholesterol (OL); control diet + 0.5% cholesterol + 10% hempseed (OLHP); control diet + 5% coconut oil (CO). After 8 weeks, blood was collected to measure ADP- and collagen-induced platelet aggregation and plasma levels of fatty acids, cholesterol, and triglycerides. The hempseed-fed animals (HP and OLHP) displayed elevated plasma levels of PUFAs and a prominent enhancement in 18:3n-6 (gamma-linolenic acid, GLA) levels, a unique PUFA found in hempseed. The cholesterol-supplemented groups (OL and OLHP) had significantly elevated plasma levels of cholesterol and triglycerides, but platelet aggregation was significantly augmented only in the OL group. The addition of hempseed to this diet (OLHP) normalized aggregation. The direct addition of GLA to the OL platelet samples blocked the cholesterol-induced stimulation of platelet aggregation. The results of this study demonstrate that when hempseed is added to a cholesterol-enriched diet, cholesterol-induced platelet aggregation returns to control levels. This normalization is not due to a reduction in plasma cholesterol levels, but may be partly due to increased levels of plasma GLA.

Topics: Animals; Blood Platelets; Body Weight; Cannabis; Cholesterol Esters; Cholesterol, Dietary; Dietary Supplements; Disease Models, Animal; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Hypercholesterolemia; Male; Platelet Aggregation; Platelet Aggregation Inhibitors; Rabbits; Seeds; Triglycerides

We studied the effects of five high-fat semi-purified diets varying at a 4% (w/w) level in either stearic, oleic, linoleic, alpha-linolenic, or gamma-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4% conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the alpha-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the gamma-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.

Topics: Adipose Tissue; alpha-Linolenic Acid; Animals; Body Composition; Body Weight; Dietary Fats; Energy Metabolism; Fatty Acids; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids, Conjugated; Male; Mice; Mice, Inbred BALB C; Oleic Acid; Stearic Acids

Plant-based n-3 polyunsaturated fatty acids (PUFA) possess a prospective antiatherogenic potential. Currant oil from Ribes nigrum L. is one of the few plant oils containing PUFAn-3 (15.3 mol%) in addition to PUFAn-6 (60.5 mol%). This study was aimed at comparing the effects of currant oil with those of lard fat, rich in saturated (43.8 mol%) and monounsaturated (47.0 mol%) fatty acids, on antioxidant parameters, the lipoprotein profile and liver lipids in rats fed on 1 % (w/w) cholesterol diets containing either 10 % of currant oil (COD) or lard fat (LFD). After 3 weeks of feeding, the COD induced a significant decrease in blood glutathione (GSH) and an increase in Cu(2+) induced oxidizability of serum lipids, but did not affect liver GSH and t-butyl hydroperoxide-induced lipoperoxidation of liver microsomes. Although the COD did not cause accumulation of liver triacylglycerols as LFD, the lipoprotein profile (VLDL, LDL, HDL) was not significantly improved after COD. The consumption of PUFAn-3 was reflected in LDL as an increase in eicosapentaenoic and docosahexaenoic acid. These results suggest that currant oil affects positively the lipid metabolism in the liver, above all it does not cause the development of a fatty liver. However, adverse effects of currant oil on the antioxidant status in the blood still remain of concern.

Topics: Administration, Oral; Animals; Antioxidants; Body Weight; Cholesterol, Dietary; Dietary Fats; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Lipid Metabolism; Lipids; Lipoproteins; Male; Microsomes, Liver; Rats; Rats, Wistar; Seeds; Thiobarbituric Acid Reactive Substances; Triglycerides

Diabetes mellitus can lead to functional and structural deficits in both the peripheral and central nervous system. The pathogenesis of these deficits is multifactorial, probably involving, among others, microvascular dysfunction and oxidative stress. The present study examined the effects of 12 weeks of treatment with a conjugate of the essential fatty acid gamma-linolenic acid and the anti-oxidant alpha-lipoic acid (GLA-LA) on functional deficits in the peripheral and central nervous system in streptozotocin-diabetic rats. Treatment was initiated 16 weeks after diabetes induction. Sciatic nerve motor and sensory conduction velocity, brainstem auditory evoked potentials and visual evoked potentials were measured in control, untreated and GLA-LA treated diabetic rats. Also, long-term potentiation, a form of synaptic plasticity used as a model for learning and memory at the cellular level, was examined in hippocampal slices. GLA-LA treatment (50 mg/kg/day) did not reverse established deficits in nerve conduction velocity or in evoked potential latencies in diabetic rats. However, GLA-LA treatment did improve long-term potentiation in the hippocampus. It is concluded that GLA-LA, which is known to improve early deficits in peripheral nerve conduction in diabetic rats, is unable to reverse late deficits. However, the compound does reverse established deficits in long-term potentiation, suggesting that at least part of its activity is specifically directed at synaptic plasticity.

Topics: Animals; Blood Glucose; Body Weight; Brain; Central Nervous System; Diabetes Mellitus, Experimental; Drug Therapy, Combination; gamma-Linolenic Acid; Male; Neural Conduction; Peripheral Nerves; Peripheral Nervous System; Rats; Rats, Wistar; Recovery of Function; Thioctic Acid

Effects of dietary fats differing in fatty acid composition on insulin-stimulated glucose metabolism in adipocytes isolated from rat white adipose tissue were compared. Rats were fed experimental diets containing various fats differing in fatty acid composition for 7 days. In the first experiment, rats were fed palm oil mainly consisting of palmitic (45.3%) and oleic acids (39.1%) or safflower oil rich in linoleic acid (71.6%). In the second trial, rats were fed palm oil, or a fat mixture rich in linoleic acid or mold oil rich in gamma-linolenic acid. Contents of fatty acids except for linoleic and gamma-linolenic acid were comparable between the fat mixture and mold oil. The former was devoid of gamma-linolenic acid and contained 42.0% linoleic acid, while the latter contained 25.9% gamma-linolenic and 15.7% linoleic acids. In the first experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed safflower oil compared to those fed palm oil. In the second experiment, the insulin-dependent increase in glucose oxidation and incorporation into lipids was higher in rats fed the fat mixture and mold oil than in those fed palm oil. However, the extent of the increase in these parameters was much greater in rats fed mold oil than in those fed the fat mixture. Therefore, dietary gamma-linolenic acid compared to linoleic acid increases glucose metabolism in response to insulin stimuli in isolated rat adipocytes.

Topics: Adipocytes; Adipose Tissue; Animals; Blood Glucose; Body Weight; Diet; Dietary Fats; gamma-Linolenic Acid; Glucose; Insulin; Lipid Metabolism; Lipids; Male; Oleic Acids; Organ Size; Palm Oil; Palmitic Acids; Plant Oils; Rats; Rats, Sprague-Dawley

We showed previously that dietary eicosapentaenoic acid [EPA, 20:5(n-3)] is antitumorigenic in the APC:(Min/+) mouse, a genetic model of intestinal tumorigenesis. Only a few studies have evaluated the effects of dietary fatty acids, including EPA and docosahexaenoic acid [DHA, 22:6(n-3)], in this animal model and none have evaluated the previously touted antitumorigenicity of alpha-linolenic acid [ALA, 18:3(n-3)], conjugated linoleic acid [CLA, 77% 18:2(n-7)], or gamma-linolenic acid [GLA, 18:3(n-6)]. Stearidonic acid [SDA, 18:4(n-3)], the Delta6-desaturase product of ALA, which is readily metabolized to EPA, has not been evaluated previously for antitumorigenic efficacy. This study was undertaken to evaluate the antitumorigenicity of these dietary fatty acids (ALA, SDA, EPA, DHA, CLA and GLA) compared with oleic acid [OA, 18:1(n-9)] at a level of 3 g/100 g in the diets of APC:(Min/+) mice and to determine whether any alterations in tumorigenesis correspond to alterations in prostaglandin biosynthesis. Tumor multiplicity was significantly lower by approximately 50% in mice fed SDA or EPA compared with controls, whereas less pronounced effects were observed in mice fed DHA (P: = 0.15). ALA, CLA and GLA were ineffective at the dose tested. Although lower tumor numbers coincided with significantly lower prostaglandin levels in SDA- and EPA-fed mice, ALA and DHA supplementation resulted in equally low prostaglandin levels, despite proving less efficacious with regard to tumor number. Prostaglandin levels did not differ significantly in the CLA and GLA groups compared with controls. These results suggest that SDA and EPA attenuate tumorigenesis in this model and that this effect may be related in part to alterations in prostaglandin biosynthesis.

Topics: 6-Ketoprostaglandin F1 alpha; alpha-Linolenic Acid; Animals; Body Weight; Dietary Fats; Dinoprostone; Docosahexaenoic Acids; Eating; Fatty Acids; Fatty Acids, Omega-3; gamma-Linolenic Acid; Genes, APC; Intestinal Neoplasms; Intestines; Linoleic Acid; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Mutation; Phospholipids

Elevated oxidative stress and impaired n-6 essential fatty acid metabolism contribute to defective nerve conduction velocity (NCV) and perfusion in diabetic rats, which may be corrected by free radical scavenger and gamma-linolenic acid (GLA) treatments. Alpha-lipoic acid (LPA) has antioxidant actions and both LPA racemate (racLPA) and GLA treatments produced benefits in clinical neuropathy trials. The aims were to study LPA action on neurovascular function in diabetic rats and to investigate potential interactions for co-treatment with GLA and other essential fatty acids. After 6 weeks of diabetes, 2 weeks of racLPA treatment corrected 20% sciatic motor and 14% saphenous sensory NCV deficits. The ED50 for motor NCV restoration was approximately 38 mg kg(-1) day(-1). racLPA also corrected a 49% diabetic deficit in sciatic endoneurial blood flow. R and S-LPA enantiomers were equipotent in correcting NCV and blood flow deficits. Treatment of diabetic rats with low doses (20 mg kg(-1) day(-1)) of racLPA and GLA, while having modest effects on their own, showed evidence of marked synergistic action in joint treatment, completely correcting motor NCV and blood flow deficits. This was also noted for the novel compound, SOC0150, which contains equimolar proportions of LPA and GLA (ED50 9.3 mg kg(-1) day(-1), containing 3.5 mg LPA). NCV effects also showed marked synergism when racLPA:GLA ratios were varied over a 1:3-3:1 range. In contrast, a compound containing LPA and the n-3 component, docosahexaenoic acid, showed similar activity to LPA alone. Thus, LPA-GLA interactions yield drug combinations and compounds with an order of magnitude increase in efficacy against experimental diabetic neuropathy and are worthy of consideration for clinical trials.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Diabetic Neuropathies; gamma-Linolenic Acid; Male; Neural Conduction; Rats; Rats, Sprague-Dawley; Saphenous Vein; Sciatic Nerve; Thioctic Acid

The effects of evening primrose oil (EPO) treatment, a source of gamma-linolenic acid, on the proportions of arachidonoyl-containing molecular species (ACMS) in sciatic nerve phosphatidylcholine and phosphatidylethanolamine were determined in conjunction with alterations in nerve conduction velocity. Normal and diabetic rats were either untreated or fed a dietary supplement containing isocalorically equivalent amounts of either EPO or corn oil for the duration of the experiment. After 8 weeks of streptozotocin-induced diabetes, nerve conduction velocity was reduced 16% and this deficit was prevented by either EPO or corn oil treatment. Neither EPO nor corn oil supplementation significantly increased the depressed proportions of ACMS. The level of the linoleoyl-containing molecular species, 16:0/18:2, was elevated in the phospholipids from untreated diabetic rats and was further increased by EPO treatment. These results are consistent with decreased activity of the delta6 desaturase that is required for arachidonic acid synthesis in vivo, but suggests that an accompanying deficit in the subsequent delta5 desaturase-catalyzed reaction may be rate-limiting. These findings indicate that maintenance of normal ACMS levels is not required for prevention of diminished nerve conduction velocity and suggest that other factors influenced by an altered polyunsaturated fatty acid pattern, such as metabolites of linoleic acid or gamma-linolenic acid other than arachidonic acid, the energy state of the nerve or the degree of membrane fluidity may contribute to impaired nerve conduction velocity in diabetic neuropathy.

Topics: Animals; Arachidonic Acid; Blood Glucose; Body Weight; Corn Oil; Diabetes Mellitus, Experimental; Dietary Supplements; Fatty Acids, Essential; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Glycerophospholipids; Linoleic Acids; Male; Neural Conduction; Oenothera biennis; Phosphatidylcholines; Phosphatidylethanolamines; Plant Oils; Rats; Rats, Sprague-Dawley; Sciatic Nerve

Altered prostanoid metabolism participates in the pathogenesis of diabetic complications. The rate-limiting enzyme in the control of prostanoid metabolism is constitutive cyclo-oxygenase (COX-1). This study examined the possibility that altered prostanoid metabolism derives from altered COX-1 expression in those tissues from diabetic rats, with characteristic changes in prostanoid production and related haemodynamics. This account also describes a procedure for estimation of minute amounts of COX-1 mRNA by reverse transcription and competitive polymerase chain reaction (RT-cPCR) amplification. In streptozotocin-diabetic rats (STZ-D, 55 mg/kg body weight), compared with age-matched controls, the level of COX-1 mRNA (in attomoles/micrograms tRNA +/- 1SD) was significantly decreased in sciatic nerve (0.50 +/- 0.26 versus 0.89 +/- 0.32 in controls; P < 0.05) and thoracic aorta (3.99 +/- 1.67 versus 8.80 +/- 2.37 in controls; P < 0.05). There were no differences in COX-1 mRNA in diabetic and control rat kidney and retina, though there was a trend towards increased expression with diabetes in the latter. Evening primrose oil (EPO) treatment increased COX-1 mRNA in nerve and retina to levels in diabetic rats that were higher than those of non-diabetic controls (1.21 +/- 0.28 for nerve and 0.065 +/- 0.017 for retina, where control retinae gave 0.031 +/- 0.020-see above for nerve). Treatment of diabetic rats with an aldose reductase inhibitor was without effect on COX-1 mRNA levels in the tissues examined. This study demonstrates that the changes in COX-1 mRNA levels in diabetic rats are organ specific and suggests that altered prostanoid metabolism can, in part, be explained by altered COX-1 expression. Apart from providing arachidonate as substrate for COX, EPO stimulates COX-1 expression in some tissues.

Topics: Aldehyde Reductase; Animals; Aorta, Thoracic; Blood Glucose; Body Weight; Cyclooxygenase 1; Cyclooxygenase 2; Diabetes Mellitus, Experimental; DNA Primers; Fatty Acids, Essential; gamma-Linolenic Acid; Gene Expression Regulation, Enzymologic; Isoenzymes; Linoleic Acids; Male; Membrane Proteins; Oenothera biennis; Plant Oils; Polymerase Chain Reaction; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Wistar; RNA, Messenger; Sciatic Nerve

Diabetes mellitus is associated with defective essential fatty acid desaturation. In experimental models this contributes to characteristic reductions in peripheral nerve conduction velocity (NCV) and blood flow, which may be corrected by dietary supplementation with gamma-linolenic acid (GLA) rich oils to bypass the delta-6 desaturation deficit. There is debate about the mechanism of this improvement, including whether it depends on synthesis of series 1 prostanoids derived from di-homo GLA or series 2 prostanoids from arachidonic acid (ARA). The aim was to assess the efficacy of two ARA-rich (approximately 39% content) oils in correcting neurovascular dysfunction in streptozotocin-induced diabetic rats. After 6 weeks of untreated diabetes, rats were treated for a further 2 weeks with 1% dietary oil supplements before assessment of sciatic motor NCV and endoneurial blood flow. NCV was 19% reduced in diabetic rats and this was largely (approximately 86%) corrected by both oil treatments. A 48% deficit in endoneurial nutritive blood flow with diabetes was approximately 70% reversed by the two oils, vascular conductance being in the non-diabetic range. Thus, nerve conduction and perfusion deficits in diabetic rats are corrected by ARA-rich oil treatment. The magnitudes of these changes were similar to expectations based on previous studies of GLA-rich oils, therefore it is likely that the neurovascular effect of increased synthesis of series 2 prostanoids makes a major contribution to the beneficial action of n-6 essential fatty acids in experimental diabetic neuropathy.

Topics: Animals; Arachidonic Acid; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Dietary Fats, Unsaturated; Fatty Acids, Essential; gamma-Linolenic Acid; Linoleic Acids; Male; Neural Conduction; Oenothera biennis; Plant Oils; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Sciatic Nerve; Streptozocin

Impaired omega-6 essential fatty acid metabolism and exaggerated polyol pathway flux contribute to the neurovascular abnormalities in streptozotocin-diabetic rats. The potential interactions between these mechanisms were examined by comparing the effects of threshold doses of aldose reductase inhibitors and evening primrose oil, alone and in combination, on neurovascular deficits. In addition, high-dose aldose reductase inhibitor and evening primrose oil treatment effects were challenged by co-treatment with the cyclo-oxygenase inhibitor, flurbiprofen, or the nitric oxide synthase inhibitor, NG-nitro-L-arginine. Eight weeks of diabetes caused an 18.9% reduction in sciatic motor conduction velocity (p < 0.001). This was only modestly ameliorated by a 0.1% dietary supplement of evening primrose oil or the aldose reductase inhibitors ZD5522 (0.25 mg.kg-1.day-1 and WAY121 509 (0.2 mg.kg-1.day-1 for the final 2 weeks. However, joint treatment with primrose oil and ZD5522 or WAY121 509 caused marked 71.5 and 82.4% corrections, respectively, of the conduction deficit. Sciatic nutritive blood flow was 43.1% reduced by diabetes (p < 0.001) and this was corrected by 67.8% with joint ZD5522 and primrose oil treatment (p < 0.001). High-dose WAY121 509 (10 mg. kg-1.day-1 and primrose oil (10% dietary supplement) prevented sciatic conduction velocity and nutritive blood flow deficits in 1-month diabetic rats (p < 0.001). However, these effects were abolished by flurbiprofen (5 mg.kg(-1).day-1 and NG-nitro-L-arginine (10 mg.kg-1.day-1) co-treatment (p < 0.001). Thus, the data provide evidence for synergistic interactions between polyol pathway/nitric oxide and essential fatty acid/cyclo-oxygenase systems in the control of neurovascular function in diabetic rats, from which a potential therapeutic advantage could be derived.

Topics: Acetanilides; Aldehyde Reductase; Analysis of Variance; Animals; Arginine; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Dietary Fats, Unsaturated; Enzyme Inhibitors; Erythropoietin; Fatty Acids, Essential; Flurbiprofen; Fructose; gamma-Linolenic Acid; Inositol; Linoleic Acids; Male; Neural Conduction; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Oenothera biennis; Plant Oils; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Regression Analysis; Sciatic Nerve; Sorbitol; Sulfones

To investigate the involvement of (n-6) essential fatty acids, such as linoleic acid [18:2(n-6)] or gamma-linolenic acid [18:3(n-6)], and of prostaglandins on liver lipid accumulation in Japanese quail.. Effects of graded amounts of aspirin, which inhibits prostaglandin synthesis, on liver weight were determined in experiment 1. Experiment 2 was designed to clarify the effect of dietary essential fatty acid sources and inhibition of prostaglandin synthesis on the liver fat and fatty acid profile.. Female Japanese quail.. In experiment 1, from 1 to 3 weeks of age, birds were fed ad libitum the essential fatty acids-free or linoleic acid-adequate (2%) diets with graded amounts of aspirin (0, 0.1, 0.2, and 0.4%). In experiment 2, from 1 to 4 weeks of age, birds were fed the same amount of essential fatty acids-free, linoleic acid-adequate, or gamma-linolenic acid (0.4%) diets with (0.2%) or without aspirin.. In experiment 1, in groups given the essential fatty acids-free diet, liver weight increased with an increase in dietary aspirin concentration. In experiment 2, gamma-linolenic acid completely prevented liver triacylglycerol and cholesterol accumulation induced by the essential fatty acids-free diet. Aspirin treatment significantly lowered plasma prostaglandin F2 alpha concentration, but did not affect liver lipid concentrations. In groups fed the essential fatty acids-free diets, however, aspirin treatment increased liver weight and liver triacylglycerol concentration by 20 and 40%, respectively.. gamma-Linolenic acid or its metabolites, but not linoleic acid itself, are important factors in reducing fatty liver in Japanese quail with the essential fatty acids-deficient condition.

Topics: Animals; Aspirin; Body Weight; Coturnix; Dietary Fats; Dinoprost; Fatty Acids, Essential; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Female; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Liver; Organ Size; Prostaglandins

Interest in the modulation of renal diseases by polyunsaturated fatty acids (PUFA) led this group to examine the effects of borage oil (BO) and corn oil (CO) in the rat 5/6-renal-ablation model. BO is a rich source of gamma-linolenic acid (GLA; 18:3n-6), which is elongated to dihomogamma-linolenic acid (DGLA; 20:3n-6). CO is a rich source of linoleic acid (LA; 18:2n-6), a GLA and arachidonic acid (AA; 20:4n-6) precursor. The purpose of this study was to assess whether an increased DGLA:AA ratio as provided by BO would confer benefits beyond those provided by LA present in corn oil. Forty rats were used for the experiment. Seven rats were used for presurgery measurements. The remaining animals were subjected to 5/6 nephrectomy. Surviving rats (N = 30) were fed regular laboratory diet (RLD) for 7 days, at which time seven rats were used to obtain 1-wk postnephrectomy data. The remainder were then allocated to receive either RLD (N = 8), 15% BO (N = 8), or 15% CO (N = 7) diets for 20 wk. Body weight, renal phospholipid levels, renal function (proteinuria and GFR), glomerular histology, glomerular macrophage infiltration, urinary prostaglandin levels (thromboxane B2 (TxB2), 6-keto-PGF1 alpha), plasma lipid levels, and blood pressure were measured. Diets were well tolerated by all groups with a similar age-related gain in weight throughout the study. Efficacy of the PUFA diets was confirmed by alteration in renal tissue phospholipids; LA decreased in the RLD and BO groups, but not in the CO group. AA was higher in the BO and CO rats, but only the BO group showed a rise in GLA and DGLA incorporation. Proteinuria increased progressively in the RLD group but remained at 1-wk postsurgery levels in the BO and CO groups. Decline in GFR and mesangial expansion were significantly lessened by BO supplementation only. Both PUFA diets limited glomerulosclerosis and macrophage infiltration, but direct comparisons between BO and CO groups revealed significantly less glomerulosclerosis and macrophage infiltration in the BO group. Both BO and CO attenuated the rise in the TxB2 excretion rate and restored the 6-keto-PGF1 alpha:TxB2 ratio to the 1-wk postsurgery level. Plasma lipid levels rose in all groups, but the rise in cholesterol level was less in the BO and CO rats, CO being the most efficacious in this regard. BP increased progressively in RLD rats, but not in the BO and CO groups, BO providing a markedly greater hypotensive effect. In summary, both CO and BO supplemen

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Arachidonic Acid; Body Weight; Corn Oil; Dietary Fats, Unsaturated; gamma-Linolenic Acid; Glomerulosclerosis, Focal Segmental; Hypertension, Renal; Kidney; Lipids; Macrophages; Male; Nephrectomy; Phospholipids; Plant Oils; Rats; Rats, Sprague-Dawley

Reduced nerve conduction velocity (NCV) in experimental diabetes can be prevented by evening primrose oil (EP), which is rich in gamma-linolenic acid (GLA). This study examined the efficacy of natural GLA sources, blackcurrant (BC), borage (BO) and fungal (FU) oils, compared with EP, in correcting motor and sensory NCV deficits in streptozotocin-diabetic rats, and any potential contribution of thromboxane (TX) A2 synthesis using the TX antagonist, ZD1542, alone and jointly with GLA-rich oils. Sciatic motor NCV, 20% reduced by 8 weeks of diabetes, was partially (16%) corrected by 2 weeks ZD1542 treatment. 1% BC, BO, FU and EP dietary supplementation caused 11%, 32%, 41% and 53% NCV ameliorations, respectively. A 2% EP diet, more closely matching the GLA intake from the other oils, caused 67% correction. Joint oil/ZD1542 treatment produced further motor NCV improvements for BC and, particularly, BO. A 13% sensory saphenous NCV deficit in diabetic rats was ameliorated by 31%, 24%, 49%, 81%, 70% and 94% for ZD1542, BC, BO, FU, EP and 2% EP, respectively. Joint ZD1542-oil treatment further improved NCV, particularly for BO. Therefore, efficacy against experimental diabetic neuropathy is not predictable from the GLA content of natural oils, EP consistently outperforming BC, BO and FU. Increased TXA2 with diabetes made a minor contribution to NCV deficits, but blockade improved the response to BO.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Dioxanes; Drug Therapy, Combination; Enzyme Inhibitors; Fatty Acids, Essential; gamma-Linolenic Acid; Linoleic Acids; Male; Neural Conduction; Oenothera biennis; Plant Oils; Pyridines; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Streptozocin; Thromboxane-A Synthase

It has been reported that gamma-linolenic acid (GLA)-rich diets suppress mammary carcinogenesis and transplanted tumor growth and that GLA inhibits the growth of cultured human cancer cell lines. We compared the effects of dietary GLA and linoleic acid (LA) on the growth of MDA-MB-435 human breast cancer cells and their expression of the metastatic phenotype in vivo and in vitro. Athymic nude mice (30/dietary group) were fed isocaloric diets containing 20% (wt/wt) fat but providing 8% GLA or LA for 7 days, and 10(6) tumor cells were then injected into a thoracic mammary fat pad. The diets were continued for a further 11 weeks. The primary tumor growth rates were similar in mice from the two dietary groups; there was a nonstatistically significant trend for the incidence of macroscopic lung metastases and the total lung metastatic volumes to be higher in the GLA-fed mice (79% and 40.1 +/- 13.9 mm3) than in the LA-fed mice (64% and 15.5 +/- 5.4 mm3). The tumor cell phospholipids from the 8% GLA-fed mice contained significantly lower LA levels but higher arachidonic acid levels (both p < 0.001) than those from 8% LA-fed mice. Also the arachidonate-derived eicosanoids (prostaglandin E, leukotriene B4, and 5-, 12-, and 15-hydroxyeicosatetraenoic acids) were significantly higher in tumors from the 8% GLA group. Zymography showed higher 92-kDa type IV collagenase activity in tumors from 8% GLA-fed mice. In vitro, GLA and LA, at 0.5-2 micrograms/ml, stimulated MDA-MB-435 cell growth; 10 micrograms/ml was mildly inhibitory. Whereas LA stimulated tumor cell invasion and 92-kDa type IV collagenase production in vitro, GLA inhibited invasion and did not induce activity of the proteolytic enzyme. Our results do not support the hypothesis that supplementation with GLA would exert a beneficial effect on the progression of an existing breast cancer, perhaps because it is metabolized in vivo to arachidonate-derived eicosanoids that are known to be involved in the metastatic process.

Topics: Animals; Arachidonic Acid; Body Weight; Breast Neoplasms; Cell Division; Collagenases; Dietary Fats; Eicosanoids; Fatty Acids; Female; gamma-Linolenic Acid; Humans; Linoleic Acid; Linoleic Acids; Lung Neoplasms; Mice; Mice, Nude; Neoplasm Invasiveness; Phospholipids; Tumor Cells, Cultured

Rats were fed for 6 weeks with a 40% galactose diet to chronically stimulate the polyol pathway. Sciatic motor and saphenous sensory nerve conduction velocity deficits of 22% and 14% respectively developed. Treatment with evening primrose oil or doxazosin from galactosaemia induction partially (approximately 60%) prevented the development of reduced motor and sensory conduction, the former treatment being more successful than the latter. Sciatic nerve resistance to hypoxic conduction failure was 49% increased by galactosaemia. This abnormality was 27% and 43% prevented by doxazosin and evening primrose oil respectively. Galactosaemic sciatic nerves had a 10% increase in water content and endoneurial capillary density was 24% reduced. While neither treatment affected water content, both caused angiogenesis, elevating capillary density by approximately 16%. The data support the hypothesis that, as in experimental diabetes mellitus, the main effect of polyol pathway activation on peripheral nerve function occurs indirectly via a neurovascular action.

Topics: Animals; Body Weight; Doxazosin; Fatty Acids, Essential; Galactose; gamma-Linolenic Acid; Hypolipidemic Agents; Hypoxia; Linoleic Acids; Male; Neural Conduction; Oenothera biennis; Plant Oils; Rats; Rats, Sprague-Dawley; Sciatic Nerve

1. The importance of linoleic acid (18:2n-6) itself and of dietary gamma-linolenic acid (18:3n-6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g gamma-linolenic acid/kg, or 20 g linoleic acid/kg to an n-6 EFA-free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets. 2. Liver weight and lipid content in birds fed the 2 and 4 g gamma-linolenic acid/kg diet were significantly lower than those in birds fed the gamma-linolenic acid-free diet. However, no significant difference was observed between the gamma-linolenic acid- and linoleic acid-supplemented diets. 3. In birds fed the 4 g gamma-linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to gamma-linolenic acid of approximately 20% of whole body content. 4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of gamma-linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.

Topics: Analysis of Variance; Animals; Body Weight; Chromatography, Gas; Coturnix; Dietary Fats, Unsaturated; Fatty Acids; Fatty Acids, Essential; Female; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Lipid Metabolism; Lipids; Liver; Organ Size; Safflower Oil; Weight Gain

The subcutaneous air pouch formed in Sprague-Dawley rats was used to study the effect of diets enriched in black currant seed oil (BCSO) on acute inflammation induced by monosodium urate crystals. The BCSO enriched diet suppressed significantly both the cellular and fluid phases of inflammation (polymorphonuclear leucocyte and exudate accumulation). In contrast, administration of normal chow or of a diet enriched in safflower oil (polyunsaturated fatty acid control) did not influence monosodium urate crystal-induced inflammation in this model. The findings indicate that a diet which provides both n-6 (gammalinolenic acid) and n-3 (alpha-linolenic acid) fatty acids as substrates alternative to arachidonatic acid for oxidative metabolism, modifies monosodium urate crystal-induced acute inflammation.

Topics: Administration, Oral; Animals; Body Weight; Diet; Female; gamma-Linolenic Acid; Inflammation; Leukocyte Count; Male; Neutrophils; Plant Oils; Rats; Rats, Sprague-Dawley; Safflower Oil; Uric Acid

Obese Zucker rats (fa/fa) have low levels of arachidonic acid (AA) in liver phospholipids (PL). We have previously shown that a 70% gamma-linolenate concentrate (GLA; an AA intermediate) fed at a fixed dose (0.07 g/day) normalized hepatic PL AA and reduced weight gain selectively in the obese animals. In a follow-up study, 16 obese (fa/fa) and 16 lean (Fa/Fa) 4-week-old male rats were randomized into 4 groups of 8 each and gavaged daily with soybean oil (SOY) containing 55% 18:2omega6 (an AA precursor) or GLA, using a progressive dose (< or = 5% of total calories) based on body weight. A defined diet with 11% of energy as SOY was fed ad libitum for 60 days. GLA obese had lower body weight (p<0.0001) and 60-day cumulative food intake (p<0.05) compared to SOY obese, but neither parameter differed between the lean groups. For the last twenty days cumulative food intake was identical for GLA obese and SOY lean, whereas SOY obese consumed 18% more (p<0.05). Thus the progressive dose of GLA selectively suppressed hyperphagia in obese Zucker rats. Erythrocytes collected at 15-day intervals showed parallel increases in AA in both genotypes over time, suggesting normal AA availability during rapid growth. Thus, the reduced PL AA in the livers from the obese rats probably reflects impaired distribution in selected tissues rather than reduced hepatic production. Due to the potential health risks of enriching tissue lipids with AA, great caution is advised in considering GLA as therapy for human obesity.

Topics: Adipose Tissue; Animals; Anti-Obesity Agents; Body Composition; Body Weight; Dietary Supplements; Disease Models, Animal; Eating; Energy Metabolism; Erythrocytes; Fatty Acids; gamma-Linolenic Acid; Genotype; Glycine max; Growth; Hyperphagia; Linoleic Acid; Lipid Metabolism; Lipids; Liver; Male; Obesity; Phospholipids; Rats; Rats, Zucker; Time Factors; Weight Gain

Alterations in release of endothelium-derived vasomotor agents could underlie microvascular and neuropathic complications in diabetes. This study examined release of the potent vasodilator prostacyclin, measured as immunoreactive 6-keto prostaglandin F1 alpha, from rat lung, kidney and peripheral nerve. Tissues were taken from control and streptozotocin-diabetic rats which had been treated for 8 weeks with either evening primrose oil (EPO) or, as a control for lipid intake, coconut oil (CO). Lung and kidney slices were incubated in the presence of acetylcholine (ACh), the calcium ionophore 4-Br-A23187, arachidonic acid (AA) or without agonist (basal). Segments of sciatic nerve, with their epineuria punctured, were incubated with or without 4-Br-A23187. Basal prostacyclin release from the lung was significantly higher in rats treated with EPO irrespective of diabetic state (increased by 60% in controls and by 77% in diabetics). Levels were reduced in CO-diabetics compared to EPO-controls (53% reduction) and CO-controls (30% reduction), although this did not reach statistical significance in the latter. Basal prostacyclin release was also significantly reduced in the kidney from CO-diabetics (40% reduction compared to CO-controls and 56% reduction compared to EPO-controls). In the presence of AA, lung prostacyclin release was significantly lower in CO-diabetic rats compared to all other groups (40% reduction compared to EPO-diabetics and 60% compared to both control groups) but there were no differences in renal release between any group. Prostacyclin release by nerves from CO-diabetic rats was significantly reduced (by 91-93%) compared to all other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Glucose; Body Weight; Coconut Oil; Diabetes Mellitus, Experimental; Drinking Behavior; Epoprostenol; Fatty Acids, Essential; Feeding Behavior; gamma-Linolenic Acid; Kidney; Linoleic Acids; Lung; Male; Nervous System; Oenothera biennis; Plant Oils; Rats; Rats, Wistar

The effectiveness of dietary n-3 plant and marine fatty acids and n-6 gamma-linolenic acid (GLA) was tested as an antimetastatic modality in the experimental model of metastasis of 13762MAT:B mammary adenocarcinoma cells. Weanling female Fischer 344 rats were placed on one of the following diets: 1-23.52% blackcurrant oil (BCO), II-23.52% corn oil (CO), III-15.52% BCO + 8% fish oil (FO), IV-20.52% FO + 3% CO, and V-5% CO. After 8 weeks, 15 rats per group were injected i.v. with 10(5) cells and diets were continued until sacrifice. In the 23.52% CO group (II), the number of small (< 2 mm) and large (> 2 mm) lung metastatic foci and their total volume were significantly greater than the BCO- and/or FO-fed groups (I, II and IV). Although the number of small metastatic foci was comparable in the 5% and 23.52% CO groups, the number of large foci and the total tumor volume were reduced in the 5% CO group. These results suggest that, compared to a low-corn oil diet or a high-fat diet containing a mixture of marine and plant n-3 fatty acids plus n-6 GLA, a 23.52% corn oil diet can enhance experimental metastasis of mammary adenocarcinoma cells. Total number of metastatic foci and tumor volume were the smallest in group III, receiving a combination of plant and marine n-3 fatty acids.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Body Weight; Fatty Acids, Omega-3; Female; Fish Oils; gamma-Linolenic Acid; Linolenic Acids; Lung Neoplasms; Mammary Neoplasms, Experimental; Neoplasm Metastasis; Phospholipids; Plant Oils; Rats; Rats, Inbred F344; Survival Analysis

1. The aims of this study were first, to examine whether deficits in nerve conduction in streptozotocin-diabetic rats could be reversed by a 10% dietary supplement of evening primrose oil. Second, to determine the time-course of reversal, and third, to assess whether the effects could be blocked by the cyclo-oxygenase inhibitor flurbiprofen (5 mg kg-1 day-1). 2. One-month diabetes produced 20% and 15% deficits in sciatic motor and saphenous sensory conduction velocity respectively, which were maintained over 2 months diabetes. 3. The effect of 1-month evening primrose oil treatment on abnormalities caused by an initial month of untreated diabetes was examined. Motor and sensory nerve conduction velocity were restored to the non-diabetic level. 4. Resistance to hypoxic conduction failure was investigated for sciatic nerve trunk in vitro. The 80% conduction failure times were 29% and 55% prolonged by 1- and 2-month diabetes respectively. Evening primrose oil did not reverse the increased hypoxic resistance following 1-month untreated diabetes. 5. Sciatic nerve endoneurial capillary density was not significantly affected by diabetes, but was 16% increased in diabetic rats with reversal by evening primrose oil treatment for 1 month compared to 2-month untreated diabetes. 6. Serial motor conduction velocity measurement after 3-month untreated diabetes revealed complete normalization by evening primrose oil within 4 days. Cessation of treatment resulted in a rapid decline in conduction velocity over 24 h. 7. In a preventive study of 2-month duration, 6 groups of rats were used. These comprised non-diabetic controls, diabetic rats, and evening primrose oil-treated diabetic rats, both with and without flurbiprofen treatment. Flurbiprofen had no significant effect in non-diabetic rats, but produced an 11% worsening of motor conduction velocity and a 21% reduction of sciatic capillary density in diabetic rats. Evening primrose oil prevented the decreases in conduction velocity and increased hypoxic resistance with diabetes, and caused a 23% increase in capillary density. Flurbiprofen completely blocked the effect of evening primrose oil on conduction velocity, resistance to hypoxia, and capillarization.8. Six main conclusions were reached. First, evening primrose oil rapidly reverses conduction deficits in diabetic rats. Second, the effects of treatment may be very short-lived, suggesting a primary metabolic action. Third, evening primrose oil cannot reverse establ

Topics: Action Potentials; Animals; Body Weight; Capillaries; Cyclooxygenase Inhibitors; Diabetes Mellitus, Experimental; Fatty Acids, Essential; Flurbiprofen; gamma-Linolenic Acid; Hypoxia; Linoleic Acids; Male; Motor Neurons; Neural Conduction; Neurons; Neurons, Afferent; Oenothera biennis; Peroneal Nerve; Plant Oils; Prostaglandins; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Sciatic Nerve

1. This study examined the effects of dietary essential fatty acid supplementation (5% (w/w) evening primrose oil) upon sciatic motor nerve conduction velocity and 86Rb+ pumping in sciatic nerve endoneurial preparations in rats with 4 to 5 weeks of streptozotocin-induced diabetes. 2. Control diabetic rats (dietary supplementation with 5% (w/w) hydrogenated coconut oil) exhibited a reduction in motor nerve conduction velocity (16%; P less than 0.05) compared to similarly-fed non-diabetic controls, but there was no significant alteration in ouabain-sensitive 86Rb+ pumping, a parameter reflecting activity of the Na+/K+ pump. 3. Treatment of diabetic rats with evening primrose oil prevented completely the development of the motor nerve conduction velocity deficit without affecting the severity of diabetes. Evening primrose oil treatment did not significantly affect motor nerve conduction velocity of non-diabetic animals. 4. Evening primrose oil treatment caused a significant reduction in activity of the Na+/K+ pump in sciatic nerves of diabetic animals (45%; P less than 0.05). 5. These results suggest that the acute conduction velocity defect arising in streptozotocin-diabetic rats, and the actions of evening primrose oil upon this, are independent of any effect on activity of the Na+/K+ pump. Other putative mechanisms are discussed.

Topics: Animals; Body Weight; Diabetes Mellitus, Experimental; Diet; Fatty Acids, Essential; gamma-Linolenic Acid; Linoleic Acids; Male; Motor Neurons; Neural Conduction; Oenothera biennis; Plant Oils; Rats; Rats, Inbred Strains; Rubidium Radioisotopes; Sciatic Nerve; Sodium-Potassium-Exchanging ATPase

Male rats were fed diets containing olive (OO) or evening primrose (EPO) oil (10% w/w), with or without added cholesterol (1% w/w). After 6-week feeding, the lipid and fatty acid compositions, fluidity, and fatty acid desaturating and cholesterol biosynthesis/esterification related enzymes of liver microsomes were determined. Both the OO and EPO diets, without added cholesterol, increased the contents of oleic and arachidonic acids, respectively, of rat liver microsomes. The results were consistent with the increases in delta 9 and delta 6 desaturation of n-6 essential fatty acids and the lower microviscosity in the EPO group. Dietary cholesterol led to an increase in the cholesterol content of liver microsomes as well as that of phosphatidylcholine (PC). The cholesterol/phospholipid and PC/PE (phosphatidylethanolamine) ratios were also elevated. Fatty acid composition changes were expressed as the accumulation of monounsaturated fatty acids, with accompanying milder depletion of saturated fatty acids in rat liver microsomes. In addition, the arachidonic acid content was lowered, with a concomitant increase in linoleic acid, which led to a significant decrease in the 20:4/18:2 ratio in comparison to in animals fed the cholesterol-free diets. Cholesterol feeding also increased delta 9 desaturase activity as well as membrane microviscosity, whereas it decreased delta 6 and delta 5 desaturase activities. There was a very strong correlation between fluidity and the unsaturation index reduction in the membrane. Furthermore, the activity of hydroxymethylglutaryl-CoA reductase increased and the activity of acyl-CoA:cholesterol acyltransferase decreased in liver microsomes from both cholesterol-fed groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Cholesterol, Dietary; Delta-5 Fatty Acid Desaturase; Eating; Fatty Acid Desaturases; Fatty Acids; Fatty Acids, Essential; Fluorescence Polarization; Fluorescent Dyes; gamma-Linolenic Acid; Hydroxymethylglutaryl CoA Reductases; Intracellular Membranes; Linoleic Acids; Linoleoyl-CoA Desaturase; Lipid Metabolism; Liver; Male; Membrane Fluidity; Microsomes, Liver; Oenothera biennis; Olive Oil; Organ Size; Plant Oils; Rats; Rats, Wistar; Stearoyl-CoA Desaturase; Sterol O-Acyltransferase

The effects of addition of evening primrose oil (EPO) to a mink diet in the breeding season on the reproductive performance and kit and female performance during the lactation period were investigated in an experiment with 4 groups of male and female mink. Matings were carried out so that control males were mated to both control and supplemented females. Similarly, supplemented males mated both control and supplemented females. Reproductive results were evaluated both on a group basis and as an effect of male or female treatment, respectively. After males supplemented with EPO, there was a tendency for reduced rate of stillborn kits and kit losses during the first 21 days of life. These effects could not be explained physiologically. Female treatment did not affect reproductive performance, but there was a tendency for lower weight losses during lactation for EPO-supplemented females. Kit performance during the lactation period was independent of experimental treatment.

Topics: Animal Feed; Animals; Body Weight; Fatty Acids, Essential; Female; Food, Fortified; gamma-Linolenic Acid; Lactation; Linoleic Acids; Litter Size; Male; Mink; Oenothera biennis; Plant Oils; Reproduction

Spontaneously hypertensive rats (SHR) at 4 weeks of age were fed a diet supplemented with sunflowerseed oil (SO), evening primrose oil (EPO), fish oil (FO) or EPO + FO for 22 weeks. A diet with commercially available pellets served as control. Systolic blood pressure was significantly lower during and after FO, EPO and EPO + FO, whereas the lower level after SO was not significant when compared with the controls. Serum triglycerides and total cholesterol were lowest after EPO followed FO. The combination of both EPO and FO resulted in unexpected high values of triglycerides and cholesterol. HDL-cholesterol was likewise highest after EPO + FO. The results indicate a quantitatively different depression of blood pressure and serum lipids from SHR by individual polyunsaturated fatty acids (PUFA).

Topics: Animals; Blood Pressure; Body Weight; Cholesterol, HDL; Fatty Acids, Essential; Fish Oils; Food, Fortified; gamma-Linolenic Acid; Heart Rate; Hypertension; Hypolipidemic Agents; Linoleic Acids; Lipids; Male; Oenothera biennis; Plant Oils; Rats; Rats, Inbred SHR; Sunflower Oil; Triglycerides

In addition to their usual diet, nine Type 1 (insulin-dependent) diabetic men and ten male control subjects took 20 g d, alpha-tocopheryl acetate enriched evening primrose oil (14.45 g 18:2c,omega 6, 1.73 g 18:3c,omega 6, 400 mg d,alpha-tocopheryl acetate) daily for one week. At start, diabetic patients had more 14:0, 15:0 and 18:2c,omega 6, and less 16:0, 16:1c,omega 7, 18:1c,omega 7, 18:3c,omega 6, 20:3c,omega 9, 20:3c,omega 6, 20:4c,omega 6 and 22:6c,omega 3 in plasma, erythrocytes and/or platelets. Furthermore, they had lower 16:1c,omega 7/16:0, 18:1c,omega 7/16:0, and 20:4c,omega 6/20:3c,omega 6 ratios and a higher 20:3c,omega 6/18:3c,omega 6 ratio. In diabetic patients, alpha-tocopherol levels in erythrocytes were lower, whereas those in plasma were normal. In both groups, oil intake changed fatty acid profiles. Most markedly, 20:3c,omega 6 increased, whereas the ratios 20:3c,omega 6/18:3c,omega 6 and 20:4c,omega 6/20:3c,omega 6 decreased. 20:4c,omega 6 increased in control subjects, but not in diabetic patients. Erythrocytes and platelets responded differently in their fatty acid profiles. alpha-tocopherol rose in plasma and, although less for diabetic patients, in erythrocytes. In diabetic patients as well as in control subjects, erythrocyte count, haemoglobin level, mean corpuscular haemoglobin content and concentration increased and glycosylated haemoglobin percentage decreased without an apparent decline in blood glucose levels. Plasma beta-thromboglobulin and platelet factor 4 decreased, especially in diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Blood Platelets; Body Height; Body Weight; Diabetes Mellitus, Type 1; Erythrocytes; Erythropoiesis; Fatty Acids, Essential; Fatty Acids, Nonesterified; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Glycated Hemoglobin; Hemoglobins; Humans; Hypolipidemic Agents; Insulin; Linoleic Acids; Male; Oenothera biennis; Plant Oils; Reference Values

The effects of dietary gamma-linolenic acid supplementation in the form of evening primrose oil were examined in pregnant zinc-deficient rats and subsequently in their newborn pups. This supplementation was beneficial, since it reduced pup mortality, increased mean litter size and maintained appetite throughout two thirds of the gestation period. Consequently, gamma-linolenic acid seems to correct some of the biological effects of zinc deficiency. It is suggested that evening primrose oil could be used in cases of zinc deficiency caused by metabolic disturbances.

Topics: Animals; Body Weight; Diet; Fatty Acids, Essential; Female; Fetal Death; gamma-Linolenic Acid; Linoleic Acids; Linolenic Acids; Oenothera biennis; Plant Oils; Pregnancy; Pregnancy, Animal; Rats; Rats, Inbred Strains; Zinc

We studied the effect of sex on the distribution of long-chain n-3 and n-6 fatty acids in essential fatty acid-deficient rats fed gamma-linolenate (GLA) concentrate and/or eicosapentaenoate and docosahexaenoate-rich fish oil (FO). Male and female weanling rats were rendered essential fatty acid deficient by maintaining them on a fat-free semisynthetic diet for 8 weeks. Thereafter, animals of each sex were separated into three groups (n = 6) and given, for 2 consecutive days by gastric intubation, 4 g/kg body wt per day of GLA concentrate (containing 84% 18:2n-6), n-3 fatty acid-rich FO (containing 18% 20:5n-3 and 52% 22:6n-3), or an equal mixture of the two oil preparations (GLA + FO). The fatty acid distributions in plasma and liver lipids were then examined. GLA treatment increased the levels of C-20 and C-22 n-6 fatty acids in all lipid fractions indicating that GLA was rapidly metabolized. However, the increases in 20:3n-6 were less in females than those in males, while those in 20:4n-6 were greater, suggesting that the conversion of 20:3n-6 to 20:4n-6 was more active in female than in male rats. FO treatment increased the levels of 20:5n-3 and 22:6n-3 and reduced those of 20:4n-6. The increase in n-3 fatty acids was greater in females than that in males and the reduction in 20:4n-6 was smaller. Consequently, the sum of total long-chain EFAs incorporated was greater in females than that in males. The administration of n-3 fatty acids also reduced the ratio of 20:4n-6 to 20:3n-6 in GLA + FO-treated rats indicating that n-3 fatty acids inhibited the activity of delta-5-desaturase. However, this effect was not affected by the sex difference.

Topics: Animals; Body Weight; Fatty Acids; Fatty Acids, Essential; Female; Fish Oils; gamma-Linolenic Acid; Linolenic Acids; Lipid Metabolism; Liver; Male; Rats; Rats, Inbred Strains; Sex Characteristics

The purpose of the present study was to investigate the effects of gamma linolenic acid (GLA) on cardiovascular responses to psychosocial stress (isolation) and to pressor hormones in the genetically borderline hypertensive rat (SHR X WKY). Adult male SHR X WKY were divided into two groups following five weeks of group housing. One group (GLA) received eight weeks constant flow osmotic pumps releasing 0.04 mg GLA in olive oil/kg-hr, while the second group received dummy pumps (DUM). One week following pump implantation, each group was divided into two subgroups and exposed to a four-week experimental period of either continued group housing (no stress) or isolation (stress). A two-week recovery period of group housing followed the experimental period. Blood pressure and heart rate were determined weekly by the tail cuff technique. At the end of the recovery period, animals in the no stress condition were anesthetized and received an arterial cannula for NOR and ANG infusion and direct BP recording. Then the responses to an ED50 of NOR and ANG were determined. All animals were then killed for determination of heart weight and adrenal weight. All groups had mean control period systolic BP values ranging from 143-146 mm Hg. In the no stress condition, neither GLA nor DUM altered BP over the course of the study. However, BP increased in the DUM group during all four weeks of the isolation period vs the control period (p less than 0.01), whereas BP increased only in week 1 in the GLA group (p less than 0.05). Heart rate increased during stress in the DUM group (p less than 0.05), but not in the GLA group. Vascular reactivity to NOR was unaffected by GLA administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Blood Pressure; Body Weight; Female; gamma-Linolenic Acid; Heart; Heart Rate; Hypertension; Linolenic Acids; Male; Organ Size; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Social Isolation; Stress, Physiological

Genetically obese mice (ob/ob) and their lean litter-mates were given diets iso-energetically supplemented with sucrose, hydrogenated coconut oil, safflower oil or evening primrose (Oenothera biennis) oil. Weight gain over 15 weeks was significantly greater in the evening primrose oil-supplemented obese mice than in the other groups. In all the groups of obese mice, liver total phospholipids contained proportionally less linoleic acid and more dihomo-gamma-linolenic acid and arachidonic acid than did the lean controls. As a percentage of total fatty acids, n-3 essential fatty acids (EFA) in liver and adipose tissue lipids were significantly lower in the obese mice than in the lean controls. Supplementation with EFA-rich oils (safflower and evening primrose oil) increased the proportional composition of n-6 EFA and decreased the n-3 EFA more in the liver total phospholipids of the lean than the obese mice.

Topics: Adipose Tissue; Animals; Body Weight; Epididymis; Fatty Acids, Essential; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Linolenic Acids; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Organ Size; Phospholipids; Triglycerides

Genetically diabetic mice (db/db) and their non-diabetic litter-mates were maintained for 15 weeks on diets supplemented with safflower oil or evening primrose (Oenothera bienis) oil, both essential fatty acid (EFA)-rich sources, or hydrogenated coconut oil (devoid of EFA). Plasma glucose was higher in the diabetic mice supplemented with the oils than in the unsupplemented diabetic mice. In the oil-supplemented non-diabetic mice, plasma glucose did not differ compared with the unsupplemented non-diabetic mice. The proportional content of arachidonic acid in the phospholipids of the pancreas was significantly decreased in diabetic mice, an effect which was completely prevented by supplementation with safflower or evening primrose oil but not hydrogenated coconut oil. In the liver phospholipids of the diabetic mice, dihomo-gamma-linolenic acid was proportionally increased, an effect reduced by supplementation with safflower oil but not evening primrose or hydrogenated coconut oils. In the liver triglycerides of the diabetic mice, gamma-linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid were all proportionally decreased, effects which were also prevented by safflower or evening primrose oil but not hydrogenated coconut oil. Alopecia and dry scaly skin were prominent in the diabetic mice but less extensive in the diabetic mice supplemented with EFA.

Topics: Animals; Blood Glucose; Body Weight; Diabetes Mellitus; Fatty Acids, Essential; gamma-Linolenic Acid; Linoleic Acid; Linoleic Acids; Linolenic Acids; Lipids; Liver; Mice; Mice, Inbred C57BL; Organ Size; Pancreas; Phospholipids; Skin; Triglycerides

Spontaneously hypertensive rats (SHR) were fed a basal regular diet (BD) or three different fat-supplemented diets which contained 10% hydrogenated coconut oil (HCO), 10% safflower oil (SFO), or 10% evening primrose oil (EPO). The rats received these four different diets from 4 weeks to over 24 weeks of age. The development of hypertension in SHR was significantly retarded in the EPO-supplemented animals. The blood pressure was lower in the SFO group animals as compared with the BD and HCO groups, but this did not reach significance. Sodium excretion rate in young SHR was increased in the EPO group compared with the HCO and SFO groups, and the urinary K/Na ratio was decreased in the EPO group compared with the HCO and EPO groups. Water intake and urine volume were increased in the SFO group as compared with the HCO and EPO groups. Sodium concentration in erythrocytes was decreased in the rats receiving SFO. Pressor responses to norepinephrine and angiotensin II were enhanced in the EPO and SFO groups as compared with the basal chow group. These data suggest that a dietary supplementation of EPO which contains a substantial amount of gamma-linolenic acid consistently lowers blood pressure in SHR. The mechanism is uncertain, but the effects on sodium handling may in part be responsible for the retardation of the development of hypertension. There was a difference between the EPO and the SFO groups in sodium--water handling, and to some extent in the blood pressure development in SHR.

Topics: Angiotensin II; Animals; Blood Pressure; Body Weight; Coconut Oil; Dietary Fats; Drinking; Erythrocytes; Fatty Acids; Fatty Acids, Essential; Fatty Acids, Unsaturated; gamma-Linolenic Acid; Hypertension; Linoleic Acids; Male; Norepinephrine; Oenothera biennis; Oils; Plant Oils; Potassium; Rats; Rats, Inbred SHR; Safflower Oil; Sodium

Data were collected during a three-month double-blind trial of evening primrose oil (EPO) in 100 obese females attending a hospital obesity clinic. Initial weight was not related to subsequent weight loss. There was, however, a significant correlation between change in mood and change in weight, with weight loss being associated with improved mood state and weight gain with increased disturbance. Such associations were strongest for patients who were new to the clinic, as opposed to refractory patients, and for patients who were initially depressed, as opposed to those who were not psychologically disturbed. It is suggested that new patients have a swift psychological response to even minor changes in weight and that, because of a risk of increasing depression, particular attention should be given to obese patients who fail to show any weight loss.

Topics: Adolescent; Adult; Aged; Body Weight; Depression; Double-Blind Method; Fatty Acids, Essential; Fatty Acids, Unsaturated; Female; gamma-Linolenic Acid; Humans; Linoleic Acids; Middle Aged; Obesity; Oenothera biennis; Plant Oils