Effect of testosterone supplementation on leptin release in rats after castration and/or unilateral surrenalectomy.

INTRODUCTION: The objective of this study was to examine the effect of testosterone supplementation on leptin release in rats which underwent castration and unilateral surrenalectomy. MATERIAL AND METHODS: The study was conducted on 80 adult male Wistar albino rats. Animals were divided into eight groups, with ten animals in each group. Group 1 was the Control group, Group 2 the Testosterone group, Group 3 the Castration group, Group 4 the Surrenalectomy group, Group 5 the Castration and Surrenalectomy group, Group 6 the Castration and Testosterone group, Group 7 the Surrenalectomy and Testosterone group, and Group 8 the Castration, Surrenalectomy and Testosterone group. The animals in Groups 2, 6, 7 and 8 were administered 5 mg/kg/day intramuscular testosterone propionate for four weeks. Blood samples were collected for analyses of leptin, LH, FSH and free and total testosterone levels in plasma. RESULTS: Groups 3 and 5 had the highest leptin and LH levels of all the groups (p < 0.01). Leptin and LH levels in Groups 1 and 4 were higher than those in Groups 2, 6, 7 and 8 (p < 0.01). A comparison of groups with regard to plasma FSH levels showed that the concerned parameter was significantly higher in Groups 3 and 5 than in the other groups (p < 0.01). FSH levels in Groups 1 and 4 were lower than those in all other groups (p < 0.01). The highest testosterone levels were obtained in Groups 2, 6, 7 and 8 (p < 0.01). Testosterone levels in Groups 1 and 4 were higher than those in Groups 3 and 5 (p < 0.01). CONCLUSIONS: This study demonstrates that unilateral surrenalectomy in rats does not have a significant effect on leptin release, while plasma LH levels, rather than testosterone, may be more effective on plasma leptin.