Inhibiting Effect Of 17-β-Estradiol On Experimental Insulin Resistance Induced By High Fructose In Ovariectomized Rats And Potential Mechanism

Aim To investigate the inhibiting effect and mechanisms of 17- β-estradiol on insulin resistance induced by the high fructose diet in ovariectomized rats .Methods The ovariectomized mature female Sprague - Dawley(S-D) rats were fed with the high fructose diet for eight weeks to induce insulin resistance. The physiological-dose 17-β -E2 (30μ g/Kg. d)was injected subcutaneously every day. Body weight (BW) and systolic blood pressure (SBP) were measured every week. Fasting blood suger(FBS), fasting serum insulin(FSI) and insulin sensitivity index(ISI)were measured every two weeks. Glucose tolerance, plasma triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol(LDL-C) were measured. The morphology of pancreas were analysed by HE. The vascular functions test was performed by using isolated blood vessel method. The contractive response of thoracic aorta rings induced by L-phenylephrine (PE) and the relaxative response of thoracic aorta rings induced by acetylcholine (Ach) and sodium nitroprusside (SNP) were measured. Nitric oxide synthase (NOS) inhibitor :N-nitrio-L-argine methyl ester (L-NAME) was used. The expression of insulin receptor α and glucose transporter 4 in skeletal muscle were measured by immunohistochemistry.Results Compared with the ovariectomized group ( OVX) or fructose fedgroup(F), BW (P<0. 05), SBP (P<0. 05), the levels of plasma TG, TC, LDL-C and FBS (all P<0. 05), FSI(P<0. 01) were increased significantly,the plasma HDL-C level and ISI were decreased significantly (respectly, P<0. 05, P<0. 05), glucose tolerance was decreased significantly (P<0. 05), injury of pancreatic P-cells was observed in the ovariectomized + fructose fed group. These effects were...