ABSTRACT
Objective In this study,the effects of moderate treadmill exercise and estrogen replacement treatment on the production of liver nitric oxide(NO)and the expression of endothelial nitrie oxide synthase(eNOS)and inducible nitric oxide synthase(iNOS)in ovariectomized(OVX)rats were observed.Methods Female mature SD rats were randomly divided into six groups according to their body weight:sham group(group S),sham exercise group (group S+EX),group OVX,OVX+exercise group (group OVX+EX),OVX+estrogen group(group OVX+E_2),and OVX+exercise+E_2 group(group OVX+EX+E_2).The rats ran on the treadmill at a speed of 18m/min for 60min,5 times per week.50μg/kg of E_2 was given subcutaneously three times per week to groups OVX+E_2 and OVX+EX+E_2.After 14 weeks,NO production in the liver was determined by nitrate reductase method.Protein expression of eNOS and iNOS was determined by immunohistochemistry.Results The NO content of group S was significantly lower than that of group S+EX,but significantly higher than that of group OVX.The NO content of groups OVX+EX,E_2,and OVX+EX+E_2 were significantly higher than that of group OVX.The positive reaction of eNOS mainly located in the cytoplasm of hepatocytes and endothelial cells of the hepatic sinusoids in all groups.The changing tendency after exercise or/and estrogen replacement was almost similar with that of the content of NO.The positive reaction of iNOS mainly located in the cytoplasm of hepatocytes in groups S,S+EX,E_2,and OVX+EX+E_2,while it located in the nuclei in both groups OVX and OVX+EX.Conclusion Moderate exercise and estrogen supplementation both had the same effect of upregnlated synthesis of NO in liver of ovariectomized rats.