Effects of Yohimbine on Plasma Levels of Leptin in Normal and Streptozotocin Induced Diabetic Rats

Leptin affects paraventricular nucleus of hypothalamus and reduces appetite whileactivation of ل2-adrenoceptors at this site has opposite action. the reducing effect of ل2-adrenoceptorsinhibition on body weight and appetite and also enhancing effects on lipolysis, sympathetic activationand plasma insulin levels in animals have been reported. we studied the effect of yohimbine treatment(2 mg/kg/day orally) as ل2-adrenoceptor antagonist on plasma levels of leptin, insulin and glucose andalso body weight in rats. five normal yohimbine treated, five diabetic insulin treated (10 u/kg/day) andfive diabetic insulin (l0 u/kg/day) and yohimbine (2 mg/kg/day) treated male sprague dawley rats wereused and treatment continued for six days. one blood sample before treatment and three blood samplesafter treatment (with one day interval) were collected from all rats. our results showed statisticallysignificant increase in leptin (p < 0.037) and insulin (p < 0.042) and decrease in body weight (p <0.004) in normal yohimbine treated rats. in diabetic rats insulin levels before and after treatment weresimilar in two groups but leptin, glucose and body weight were significantly reduced in yohimbine andinsulin treated compared with just insulin treated rats. the present results indicate that yohimbinetreatment can reduce body weight by increasing stimulation of lipolysis and increasing plasma levels ofleptin. this plasma leptin enhancement in normal rats may be contributed to the weight reducing effectof ل2-receptor antagonist drugs. our study introduces the ل2-receptor antagonists as body weightreducing, glucose restoring and insulin and leptin increasing drugs.