Corticosterone Inhibits Normal and FSH-Induced Testicular Recrudescence in the Lizard, Mabuya carinata

Abstract

Administration (ip) of 1, 10, or 20 μg corticosterone (alternate days for 30 days) to adult male Mabuya carinata did not affect the seasonal recrudescence of spermatogenesis whereas administration of 40 μg corticosterone did result in inhibition of spermatogenesis. Further, administration of FSH (10 IU/lizard/alternate day for 30 days) during the quiescent phase of the testicular cycle stimulated spermatogenetic and steroidogenic activity of the testis as shown by significant increases in the mean number of spermatogonia, spermatocytes, and spermatids and serum levels of testosterone. In addition there were abundant spermatozoa in the lumen of the tubules in FSH-treated lizards. Administration of 10 IU FSH + 40 μg corticosterone (per lizard on alternate days for 30 days) increased the mean number of primary and secondary spermatocytes whereas the mean number of spermatids did not show significant variation compared with that of controls. Further, the mean numbers of spermatocytes and spermatids and serum levels of testosterone were significantly less when compared to those of FSH alone treated lizards. In addition, FSH-induced development of epididymis was also inhibited by corticosterone treatment. The results indicate that corticosterone inhibits FSH-induced testicular recrudescence, possibly by suppressing testosterone secretion in M. carinata.