Adiponectin And Body Fat Distribution And Insulin Sensitivity Related Research

Objective: To study the relationship between plasm adiponectin(ADIPO) and insulin sensitivity in hyperglycemic fatty rats induced by small dosage of streptozotocin(STZ) injection and high-fat feed, and to study molecular mechanisms by which ADIPO improves IR basis on in pioglitazone intervention. Method: 40 male SD rats were divided into four groups randomly,that was:(1)N group: normal control rats fed with normal feed,(2)Obese group: high-fat fed rats; (3)HG group: small dosage (35mg/kg) of STZ injection and high-fat induced hyperglycemic fatty rats;(4)PIO group: small dosage of STZ injection and high-fat induced hyperglycemic fatty rats and treated with pioglitazone(3mg/kg/d). All rats were fed for 12 weeks. Below variables were collected: body weight,fasting plasm glucose(FBG),total cholesterol(TC),triglyceride(TG) ,fasting plasm insulin(FINS) ,free fatty acid(FFA) and levels of plasm adipocytokines(adiponectin,leptin and tumor necrosis factor α) . The level of tumor necrosis factor α(TNFα) in rats muscles and liver were check up by immunohistochemistry method, and tissue insulin sensititviy were determinated by euglycemic hyperinsulinemic clamp(M value). Results: (1)By using small dosage of STZ injection and high-fat feeding method, hyperglycemic fatty rats were produced with characteristics of hyperinsulinemia,hyperlipidemia and insulin resistance(IR). There was also IR in fatty rats without hyperglycemia. (2)The level of plasm ADIPO was reduced in fatty rats with or without hyperglycemia.(3) The level of plasm ADIPO were correlated positively with M value and negatively with TNFα,leptin and FFA, but levels of TNFα,leptin and FFA were correlated negatively with M value.(4)There were significant increase of insulin sensitivity and plasm ADIPO, and decrease of plasm TNFα,leptin and FFA in rats by PIO treatmen. Levels of TNFα in rats muscles and liver were also decreased.(5) PIO treatment could increase rats, body weights. Level of plasm ADIPO was correlated with insulin sensitivity better than with body weight. Conclusion: Fatty animals similar to human IGT can be produced by using small dosage of STZ injection and high-fat feeding, characteristics with hyperglycemia,hyperinsulinemia,hyperlipidemia and IR. ADIPO and other adipocytokines in plasm and insulin target tissues are well correlated with rats, tissue insulin sensitivity. One of mechanisms by which PIO improves IR is to increase the level of plasm ADIPO. And ADIPO can improve IR by suppression of expression and function of TNFα and by increasing of uptake and oxidation of FFA in muscles.Keywords: Insulin resistance;High-fat feeding;Obesity;Adipocytokines;Insulin increasing-sensitivity agent...