diisononyl-phthalate and Body-Weight

Osteopenia is characterized by bone loss and deterioration of trabecular bone, which leads to osteoporotic fractures. This disease is highly prevalent in industrialized areas and is associated with exposure to endocrine disrupting chemicals (EDCs). Diisononyl phthalate (DINP) is one of these EDCs and is mainly used as a plasticizer in flexible polyvinyl chloride (PVC) products. Although it is well known that exposure to DINP is harmful to humans, no studies have been reported concerning its contribution to osteopenia. Therefore, in this study, we injected DINP (2, 20, and 200mg/kg) into C3H/HeN mice for 6weeks and found that the uterus weight, bone (femur and tibia) weight, and bone length of the DINP-exposed mice were reduced compared to those of the SHAM group. On the other hand, body weight, the serum alkaline phosphatase (ALP) and inorganic phosphorus (IP) levels in the DINP treated mice were increased compared with those of the SHAM group. The tartrate-resistant acid phosphatase (TRAP) activity (bone resorption marker) was increased and the bone alkaline phosphatase (BALP) activity was lowered by the treatment with DINP as compared with the SHAM group. Furthermore, the microarchitecture of the femur and tibia in the intact mice was destroyed by the DINP injection. The tissue volume (TV), bone volume (BV), BV/TV, bone surface (BS), BS/TV, trabecular thickness (Tb.Th), and trabecular number (Tb.N) were reduced and the trabecular pattern factor (Tb.Pf), structure model index (SMI), and trabecular separation (Tb.Sp) were increased by the DINP injection. The bone mineral density (BMD) of the femur and tibia was lower in the DINP group than in the SHAM group. These results indicate that DINP contributes to an increased risk of osteopenia via destruction of the microarchitecture and enhancement of osteoclast activity.

Topics: Animals; Biomarkers; Body Weight; Bone and Bones; Bone Density; Bone Diseases, Metabolic; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Mice; Mice, Inbred C3H; Molecular Structure; Ovariectomy; Phthalic Acids

Reproductive and developmental effects of diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) were evaluated in a Japanese medaka (Oryzias latipes) multigeneration protocol. Each phthalate was administered via fish flake diets at a concentration of 20 microg/g (1 microg/g fish/day). Two controls were included, untreated and acetone carrier. The F(0) and F(1) generation adults were reared to sexual maturation and the test was ended prior to sexual maturation of the F(2) generation. Biochemical, individual, and population parameters were evaluated: testosterone metabolism, 7-ethoxyresorufin-o-deethylase (EROD) activity, survival, development, growth, gonadal-somatic index, histopathology, sex ratio, and fecundity. Male fish showed a two-fold induction of several testosterone metabolites in the DINP-treated group compared to the untreated control but not the acetone control. In a similar manner, in female fish only the DIDP-treated group expressed greater testosterone hydroxylase activity. There were neither sex- nor treatment-related differences in the results from the EROD assay. A statistically significant transient delay in red blood cell pigmentation was observed. The male-to-female ratio was consistent across treatments and the phenotypic and histological gender classifications were in agreement. Egg production was not significantly different among treatment groups. Neither phthalate elicited an effect on reproduction or development at various levels of biological organization.

Topics: Animals; Body Weight; Cytochrome P-450 CYP1A1; Diet; Embryo, Nonmammalian; Evaluation Studies as Topic; Female; Gonads; Hazardous Substances; Male; Organ Size; Oryzias; Ovum; Phthalic Acids; Survival Analysis; Testosterone

Diisononyl phthalate (DINP) is a compound widely used as a plasticizer in the production of polyvinyl chloride products. Chronic exposure to DINP leads to liver cancer in rats and mice. Many phthalates are considered to be relatively weak peroxisome proliferators (PP), a group of rodent hepatocarcinogens that cause a variety of adaptive responses in liver through the PP-activated receptor alpha (PPARalpha). The objectives of this study were to determine whether DINP-induced effects in the liver associated with carcinogenesis are mediated by PPARalpha and to identify novel gene targets of DINP. Male and female SV129 wild-type, SV129 PPARalpha-null, and B6C3F1 mice were administered DINP by gavage or in the feed. Transcript profile technology and reverse transcriptase (RT)-polymerase chain reaction (PCR) were used to identify gene targets. Dose-dependent increases in relative liver weights were dependent on PPARalpha in 10- or 12-week-old male and female mice and 30-week-old male mice. Female 30-week-old mice exhibited PPARalpha-independent increases in relative liver weights. Increases in hepatocyte proliferation, palmitoyl-CoA oxidase (PCO) activity, and levels of enzymes involved in beta- and omega-oxidation of fatty acids were shown to be dependent on PPARalpha. Five novel genes were shown to be altered in the livers of female wild-type mice after a 3-week exposure, but not in PPARalpha-null, mice. These genes included those involved in DNA repair and recombination (ATP-dependent helicase and Endonuclease III homolog), drug metabolism (Cyp2a4) and protein trafficking (FKBP-1, FKBP-13). An additional gene (Cyp2d9) was shown to be down-regulated in wild-type mice but up-regulated in PPARalpha-null mice indicating more complex regulation by PPARalpha and additional factors. These data support the hypothesis that PPARalpha plays a dominant role in mediating the effects associated with hepatocarcinogenesis after DINP exposure.

Topics: Animals; Body Weight; Bromodeoxyuridine; Carcinogens; Cell Division; Crosses, Genetic; Female; Hepatocytes; Liver Neoplasms, Experimental; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Oligonucleotide Array Sequence Analysis; Organ Size; Oxidoreductases; Phthalic Acids; Plasticizers; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA; Transcription Factors

To evaluate the impact of dietary exposure to endocrine disrupting chemicals (EDCs) during the sensitive period of brain sexual differentiation, maternal Sprague-Dawley rats were fed three representative chemicals, methoxychlor (MXC; 24, 240, and 1200 ppm), genistein (GEN; 20, 200, and 1000 ppm), or diisononyl phthalate (DINP; 400, 4000, and 20,000 ppm), from gestational day 15 to postnatal day 10. Soy-free diet was used as a basal diet to eliminate possible estrogenic effects from the standard diet. Offspring were examined in terms of anogenital distances, prepubertal organ weights, onset of puberty, estrous cyclicity, and organ weights and histopathology of endocrine organs at adult stage (week 11) as well as the volumes of sexually dimorphic nucleus of preoptic area (SDN-POA). All chemicals caused signs of maternal toxicity at high doses. MXC, at 1200 ppm, facilitated and delayed the onset of puberty in females and males, respectively, females also showing endocrine disrupting effects thereafter, such as irregular estrous cyclicity and histopathological alterations in the reproductive tract and anterior pituitary. GEN, at all doses, reduced body weight (BW) at week 11, but did not affect endocrine parameters. Treatment with DINP at 20,000 ppm resulted in degeneration of meiotic spermatocytes and Sertoli cells in the testis and decrease of corpora lutea in the ovary at week 11, although changes remained minimal or slight. The SDN-POA volume remained unchanged with all three chemicals. The results demonstrated that perinatal dietary exposure to EDCs for a limited period causes endocrine disruption in offspring only at high doses.

Topics: Administration, Oral; Animals; Body Weight; Endocrine System; Estrous Cycle; Female; Genistein; Male; Methoxychlor; Organ Size; Ovary; Phthalic Acids; Pregnancy; Prenatal Exposure Delayed Effects; Preoptic Area; Rats; Rats, Sprague-Dawley; Reproduction; Sex Differentiation; Testis

The effects of the peroxisome proliferators di-isononyl phthalate (DINP) and di-2-ethylhexyl phthalate (DEHP) were evaluated in young adult male cynomolgus monkeys after 14 days of treatment, with emphasis on detecting hepatic and other effects seen in rats and mice after treatment with high doses of phthalates. Groups of 4 monkeys received DINP (500 mg/kg/day), DEHP (500 mg/kg/day), or vehicle (0.5% methyl cellulose, 10 ml/kg) by intragastric intubation for 14 consecutive days. Clofibrate (250 mg/kg/day), a hypolipidemic drug used for cholesterol reduction in human patients was used as a reference substance. None of the test substances had any effect on body weight or liver weights. Histopathological examination of tissues from these animals revealed no distinctive treatment-related effects in the liver, kidney, or testes. There were also no changes in any of the hepatic markers for peroxisomal proliferation, including peroxisomal beta-oxidation (PBOX) or replicative DNA synthesis. Additionally, in situ dye transfer studies using fresh liver slices revealed that DINP, DEHP, and clofibrate had no effect on gap junctional intercellular communication (GJIC). None of the test substances produced any toxicologically important changes in urinalysis, hematology, or clinical chemistry; however, clofibrate produced some emesis, small increases in serum triglyceride, decreased calcium, and decreased weights of testes/epididymides and thyroid/parathyroid. The toxicological significance of these small changes is questionable. The absence of observable hepatic effects in monkeys at doses that produce hepatic effects in rodents suggests that DINP, DEHP, and clofibrate would also not elicit in primates other effects such as liver cancer. These data, along with results from in vitro hepatocyte studies, indicate that rodents are not good animal models for predicting the hepatic effects of phthalates in primates, including humans.

Topics: Administration, Oral; Animals; Anticholesteremic Agents; Body Weight; Cell Communication; Clofibrate; Diethylhexyl Phthalate; DNA Replication; Gap Junctions; Liver; Macaca fascicularis; Organ Size; Oxidation-Reduction; Peroxisome Proliferators; Peroxisomes; Phthalic Acids

Groups of 110 Fischer 344 rats/sex were fed diisononyl phthalate (DINP) at dietary levels of 0, 0.03, 0.3, and 0.6 wt% for periods up to 2 years. Interim sacrifices of 10 predesignated rats/sex/dose were at 6, 12, and 18 months with surviving animals sacrificed at 24 months. At study termination, survival was in excess of 60% for every group. At the mid or high dose, the following biological effects were noted: slight decreases in food consumption and body weight; slight increase in mortality; a dose-related increase in relative organ weights of liver and kidney; and some slight effects on urinalysis, hematologic, and clinical chemistry parameters. No peroxisome induction was observed in livers of treated rats compared with controls. No clear treatment-related nonneoplastic or neoplastic lesions were found. However, mononuclear cell leukemia (MNCL) and changes known to be associated with an increased incidence of MNCL were seen in the mid-dose and high-dose groups. A literature review suggests that MNCL is a common finding in aging F344 rats and that this increased incidence in rats treated with DINP is not relevant to man. A clear no-observed-effect level was demonstrated for all biological end points at a dietary level of 0. 03 wt% or approximately 17 mg/kg/day of DINP.

Topics: Administration, Oral; Adrenal Glands; Animals; Blood Chemical Analysis; Body Weight; Carcinogenicity Tests; Female; Hematologic Tests; Kidney; Leukemia, Experimental; Liver; Male; Microbodies; No-Observed-Adverse-Effect Level; Organ Size; Phthalic Acids; Precancerous Conditions; Rats; Rats, Inbred F344; Spleen; Survival Rate; Testis; Urine

Several phthalate esters with alcohol moieties ranging from C5-C10 chains were investigated for prenatal toxicity in 10 rats per group after gavage administration of 0, 40, 200 and 1000 mg/kg/day from gestation day 6 to 15. At 1000 mg/kg di(2-ethylhexyl) phthalate showed clear foetotoxicity, embryolethality and teratogenicity. No significant effects were recorded at 40 and 200 mg/kg. Di-711-phthalate, a phthalic ester with linear components and a predominantly alpha-methyl branching type, and di-isopentylphthalate showed a very similar spectrum of effects. Interestingly, the alcohol moiety of di-711-phthalate, 711-alcohol was developmentally inactive in a previous experiment. Di-iso-decylphthalate and three types of di-iso-nonylphthalate showed foetal effects of borderline significance at 1000 mg/kg/day.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Animals; Body Weight; Diethylhexyl Phthalate; Embryonic and Fetal Development; Esters; Female; Litter Size; Male; No-Observed-Adverse-Effect Level; Phthalic Acids; Pregnancy; Rats; Rats, Wistar; Survival Rate