concanavalin-a and Insulin-Resistance

Topics: Adenylyl Cyclases; Adipose Tissue; Binding Sites; Cell Membrane; Cell Transformation, Neoplastic; Concanavalin A; Humans; Insulin; Insulin Resistance; Iodine Isotopes; Liver; Mitogens; Neuraminidase; Receptors, Cell Surface

To determine the immune-modulatory and the hepatoprotective effects of oral administration of two soy extracts in immune mediated liver injury and non-alcoholic steatohepatitis (NASH).. Two soy extracts, M1 and OS, were orally administered to mice with concanavalin A (ConA) immune-mediated hepatitis, to high-fat diet (HFD) mice and to methionine and choline reduced diet combined with HFD mice. Animals were followed for disease and immune biomarkers.. Oral administration of OS and M1 had an additive effect in alleviating ConA hepatitis manifested by a decrease in alanine aminotransferase and aspartate aminotransferase serum levels. Oral administration of the OS and M1 soy derived fractions, ameliorated liver injury in the high fat diet model of NASH, manifested by a decrease in hepatic triglyceride levels, improvement in liver histology, decreased serum cholesterol and triglycerides and improved insulin resistance. In the methionine and choline reduced diet combined with the high fat diet model, we noted a decrease in hepatic triglycerides and improvement in blood glucose levels and liver histology. The effects were associated with reduced serum tumor necrosis factor alpha and alteration of regulatory T cell distribution.. Oral administration of the combination of OS and M1 soy derived extracts exerted an adjuvant effect in the gut-immune system, altering the distribution of regulatory T cells, and alleviating immune mediated liver injury, hyperlipidemia and insulin resistance.

Topics: Administration, Oral; Animals; Biomarkers; Blood Glucose; Chemical and Drug Induced Liver Injury; Choline Deficiency; Concanavalin A; Cytoprotection; Diet, High-Fat; Disease Models, Animal; Glycine max; Immunologic Factors; Insulin; Insulin Resistance; Lipids; Liver; Metabolic Syndrome; Methionine; Mice; Non-alcoholic Fatty Liver Disease; Plant Extracts; T-Lymphocytes, Regulatory; Time Factors; Tumor Necrosis Factor-alpha

Plasma cell differentiation antigen 1 (PC-1) is an inhibitor of insulinreceptor tyrosine-kinase. PC-1 content is elevated in muscle and adipose tissue from insulin-resistant subjects and its elevation correlates with in vivo insulin resistance. It is known that insulin resistance in uraemia may be improved with erythropoietin (EPO) and vitamin D therapy. Therefore, in this study the effects of human recombinant EPO and 1-alpha-D3 treatments on lymphocyte PC-1 expression in patients with end-stage renal failure on haemodialysis (HD) were investigated.. Lymphocyte basal, concanavalin A (Con A), and phorbol-12-myristate13-acetate (PMA)-stimulated PC-1 activity were investigated in HD patients before and after a two-month treatment with subcutaneous EPO (15 patients, 2000-3000 U thrice weekly) or oral 1-alpha-D3 (14 patients, 2 mug thrice weekly). Twenty-nine patients (16 men and 13 women), aged 22-68 years (49+/-7 years), on HD from 13 to 112 months, and 30 healthy controls participated in the study. None was obese and all had normal fasting plasma glucose.. A two-month EPO treatment produced a 41% haematocrit increase, with a rise in haemoglobin from 6.51+/-0.18 g/dL to 9.69+/-0.14 g/dL. Basal lymphocyte PC-1 activity in HD patients was found to be significantly increased (P<0.005) over the level in healthy controls. Treatment of patients with EPO decreased unstimulated lymphocyte PC-1 activity to values significantly lower than before the treatment (P<0.001). Lymphocyte Con A and PMA-stimulated PC-1 activity in patients on HD was found to be slightly increased over the level in healthy controls, but significantly reduced (P<0.005 and 0.05, respectively) after the EPO treatment. A two-month pulse oral 1-alpha-D3 treatment increased haematocrit by 21% and raised haemoglobin from 7.11+/-0.32 g/dL to 8.80+/-0.39 g/dL. This treatment normalized serum alkaline phosphatase activity and slightly reduced serum parathyroid hormone concentration. PC-1 in unstimulated and PMA-stimulated lymphocytes was unchanged, but significantly decreased (P<0.05) in Con A-stimulated lymphocytes after 1-alpha-D3 treatment. Fasting plasma glucose was not changed by the treatment.. An increased lymphocyte PC-1 activity over control was found in HD patients. A two-month EPO therapy significantly decreased PC-1 activity to the control values, suggesting that an effect on PC-1 expression could be implicated in the amelioration of insulin resistance in uraemic patients treated with EPO. Treatment with pulse oral 1-alpha-D3 had an effect only on PC-1 of Con A-transformed lymphocytes of haemodialysed patients and requires further investigation.

Topics: Adjuvants, Immunologic; Administration, Oral; Adult; Aged; Blood Glucose; Carcinogens; Concanavalin A; Diabetes Complications; Diabetes Mellitus, Type 2; Erythropoietin; Female; Humans; Hydroxycholecalciferols; Insulin Resistance; Kidney Failure, Chronic; Lymphocyte Activation; Lymphocytes; Male; Middle Aged; Phosphoric Diester Hydrolases; Pyrophosphatases; Recombinant Proteins; Renal Dialysis; Tetradecanoylphorbol Acetate

We have studied the regulation of glycogen metabolism by insulin in the insulin-sensitive nonfusing muscle cell line BC3H-1. The basal percentage of glycogen synthase I activity was not altered by insulin alone at any concentration, time of exposure, or age of cells tested. The addition of glucose or 2-deoxyglucose to the glucose- and serum-free incubation medium caused a 2-fold increase in glycogen synthase I activity over basal levels, and the effect was enhanced to 3-fold if insulin was added to the medium. Glycogen phosphorylase a activity was not altered by incubation in the presence of insulin, but was lowered by the addition of 2-deoxyglucose. This effect was also enhanced in the presence of insulin. The effect of exogenously added sugar occurred only if a 6-phosphorylatable hexose was used. The effect seen with 2-deoxyglucose was stable to Sephadex G-25 desalting, suggesting that activation of glycogen synthase was the result of a stable (covalent) modification of the enzyme. We were also able to demonstrate the presence of glucose-6-phosphate-activatable glycogen synthase phosphatase activity in the myocytes. The effect of 2-deoxyglucose in the presence or absence of insulin could be completely reversed by including cytochalasin B in the medium, suggesting that both the effect of hexose and the insulin enhancement of its effect were entirely dependent on carrier-mediated hexose uptake. Four insulin-mimetic agents, H2O2 Concanavalin A, Na orthovanadate, and antiinsulin receptor B2 serum, were also tested. Despite different mechanisms of action, each agent qualitatively mimicked insulin in the myocytes. All stimulated hexose transport, glucose incorporation into glycogen, and hexose-dependent activation of glycogen synthase in a manner not additive with insulin, but none increased basal glycogen synthase I activity in the absence of hexose. These results suggest that although insulin is capable of regulating glycogen metabolism both by increasing the uptake of sugar and by altering the activation state of glycogen synthase and phosphorylase, these effects are entirely due to the stimulation of hexose uptake, and hexose-independent actions of insulin are absent in BC3H-1 cells.

Topics: 3-O-Methylglucose; Animals; Cell Line; Concanavalin A; Deoxyglucose; Glucosephosphate Dehydrogenase; Glycogen; Glycogen Synthase; Glycogen-Synthase-D Phosphatase; Hexoses; Hydrogen Peroxide; Insulin; Insulin Resistance; Methylglucosides; Mice; Muscles; Neoplasms, Experimental; Vanadates; Vanadium

Madin-Darby canine kidney (MDCK) cells were previously shown to have few or no plasma membrane insulin binding sites (Hofmann et al: J Biol Chem 258:11774, 1983]. Accordingly, neither insulin-stimulated incorporation of [14C]glucose into glycogen, nor insulin-induced uptake of radiolabeled alpha-aminoisobutyrate ([3H]AIB) could be demonstrated. To probe for receptors, MDCK cultures were surface-labeled with Na125I or were labeled with [35S]methionine. When solubilized cells were immunoprecipitated with sera containing antibodies to the insulin receptor, and immunoprecipitates were analyzed on SDS-gel electrophoresis, no evidence for insulin receptor components was found. Also, when intact MDCK cells wee incubated first with serum containing antibodies to the insulin receptor and then with 125I-protein A, no radiolabeling of insulin receptors occurred. Various agents reported to have insulin-like activity were tested on MDCK cells. The insulinomimetic lectins concanavalin A and wheat germ agglutinin as well as hydrogen peroxide enhanced incorporation of [14C]glucose into glycogen and induced stimulated [3H]AIB uptake, whereas trypsin, vanadate, and serum containing antibodies to the insulin receptor were without effects. Altogether, these results showed that MDCK cells had few or no insulin receptors and were correspondingly insulin-insensitive. However, since insulin-associated responses could be elicited by some insulin mimickers, the post-receptor limb of response in MDCK cells was apparently intact.

Topics: Animals; Cell Line; Cell Membrane; Concanavalin A; Dogs; Glucose; Glycogen; Hydrogen Peroxide; Immune Sera; Immunosorbent Techniques; Insulin; Insulin Resistance; Kidney; Lectins; Receptor, Insulin; Trypsin; Vanadates; Vanadium; Wheat Germ Agglutinins

Topics: Animals; Concanavalin A; Culture Techniques; Cyclic AMP; Diazoxide; Homeostasis; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Liver; Lymphocytes; Obesity; Rats; Receptor, Insulin