Seasonal reproduction in the mongoose, Herpestes auropunctatus. II. Testicular responsiveness to luteinizing hormone

The male mongoose is a seasonal breeder and displays a distinct seasonal pattern in serum androgen levels. In this series of experiments testicular responsiveness to luteinizing hormone (LH) was evaluated during the breeding (active) and inactive seasons. The responsiveness of testes to LH was assessed by measuring [¹²⁵I]hCG (human chorionic gonadotropin) binding to dispersed interstitial cells and by measuring in vitro LH-stimulated androgen release by dispersed interstitial cells. The binding data indicated that there was a significantly greater concentration of $\text{LH}\text{hCG}$ binding sites/Leydig cell during the active season than during the inactive season. In contrast, dispersed interstitial cells prepared from animals trapped during the active and inactive seasons were equally responsive to small doses (“physiological”) of ovine LH (oLH); however, higher doses of oLH produced a significant depression in the interstitial cell output of androgen during the inactive season but not during the active season. These results indicate that there are seasonal differences in the responses of the testis to LH. Whether the seasonal pattern of serum androgen levels in the male mongoose is directed by seasonal changes in serum gonadotropin levels or changes in testicular responsiveness to LH is discussed.