Effect of obestatin on morphometry of testes and testosterone secretion in male rats

This study was designed to evaluate the effects of chronic intra peritoneal administration of obestatin on plasma testosterone concentrations and cellular morphometry of the testes in male Sprague Dawly rats. The treatment groups were injected with obestatin (1 nmol/100 mu l saline i.p), while the control groups received saline (100 mu l i.p) for ten consecutive days. Blood samples were collected at day 1 and 10 during the dose administration and day 5 and 15 after the dose administration. All the samples were collected at 10: 00 a. m. Testes were removed after sacrificing the rats on days 5 and 15 after the last injection. Plasma testosterone concentrations were found significantly high (p < 0.05) in the obestatin treated groups when compared with the control groups. Testicular histomorphometry revealed that, obestatin treatment caused a significant increase in the primary spermatocytes (P < 0.0001), secondary spermatocytes and spermatids (P < 0.005) and leydig cells population (p < 0.0001) both after 5 and 15 days. These findings indicated that obestatin can be a stimulator of testicular functions.