Studies on the effects of different doses of X-irradiation on the response of Leydig cells to hCG / 中国病理生理杂志

ABSTRACT

The present paper reports the effects of low and high doses of X-irradiation on hCG-induced testosterone secretion in cultured rat Leydig cells. The Leydig cells harvested from testis in immature rats were exposed to 25, 50, 75, 100, 250 mGy and 0.5, 1.0, 2.0, 4.0, 8.0 Gy X-irradiation at a dose-rate of 12.5 mGy/min and 0.51 Gy/min respectively after a preincubation for 24h. The cells were stimulated with 0.025 or 0.05 i.u./ml of hCG for 48 h in culture after X-irradiation. In low dose irradiated Leydig cells, the response to 0.05 i.u./ml of hCG in both 25 and 50 mGy groups was significantly higher than that of the control. No significant changes were found in response to 0.025 i.u./ml hCG in all the low dose groups. In high dose irradiated Leydig cells, the response to either 0,025 or 0.05 i.u./ml hCG was significantly inhibited in a dose-dependent manner. It is concluded that low dose ionizing irradiation acts synergistically with hCG in stimulation of testosterone production, while higher doses inhibit its secretion. The possible mechanisms of these effects were discussed.