Possible modulation of testosterone secretion by obestatin in pubertal male rats

The objective of the present study was to examine the effect of different doses of obeslatin on testosterone secretion in pubertal male sprague dawley rats. animals were divided into three groups. one group served as control and the other two groups were treated with 8 and 16 nmol/kg of obestatin,respectively. prior to sample collection,teflon cannula was implanted in lateral tail vein of rat and the sequential blood samples were collected 10 min before,at the time of obestatin treatment (0 min) and then at 10 min intervals upto 40 min. in heparinized syringes. the whole sampling was carried out under diethyl ether anesthesia. plasma testosterone levels were determined by using enzyme immunoassay (eia). administration of obestatin (8 nmol/kg) in animals resulted in a significant (p<0.05) increase in mean plasma testosterone concentrations at 10 and 20 min after obestatin administration. highly significant (p<0.001) increase in testosterone concentrations were observed at 30 min which then declined at 40 min. at dose of 16 nmol/kg in pubertal animals,a significant increase (p<0.05) was noticed in testosterone secretion at 20 and at 30 min after obestatin administration. plasma testosterone concentrations then declined after 40 min. the present study suggests that this peptide may be involved in the regulation of testosterone secretion in pubertal male rats. copyright 2011 zoological society of pakistan.