The effects of thyroid hormones on the secretion of testosterone in rat leydig cell

Objective:To investigate the impact of thyroid hormones on testosterone secretion in rat Leydig cells Methods:The rat′s Leydig cells were cultured and exposed to a series of concentrations of T 3 (0 μg/ml, 0 01 μg/ml, 0 1 μg/ml, 1 and 10 μg/ml) Basal and challenged testosterone levels were measured The distinction of Leydig cells′ secretion in vitro was evaluated between different thyroid function groups Results:There were no changes in testosterone levels when normal Leydig cells were exposed to T 3 directly However, an impaired secretion ability of testosterone in basal or in stimulated conditions was found in the Leydig cells from both hyper and hypo thyroidism rats ( P 0 01) Conclusion: The Leydig cells from normal rats had no response to thyroid hormone in vitro, but those from hyper or hypo thyroxinemia rats showed impaired testosterone secretion.