电离射辐致大鼠离体Leydig细胞对hCG反应性变化机理的初探

本实验采用幼年雄性大鼠睾丸Leydig细胞离体单层培养法,研究hCG对Leydig细胞睾酮和cAMP生成的影响,并探讨了不同剂量X线对Leydig细胞辐射效应的发生机理。实验结果表明,hCG能明显促进Leydig细胞睾酮和cAMP生成。细胞预培养24h接受不同剂量X线照射,停照后加入外源性hLCG(0.05IU/ml)继续培养48h,小剂量辐射(25～250mGy,剂量率12.5mGy/min)在25,50mGy剂量组引起Leydig细胞对hCG反应性增高,睾酮生成量明显高于对照组,细胞内cAMP含量也发生相应变化;大剂量辐射后(0.5～8.0Gy,剂量率0.5Gy/min),Leydig细胞在各剂量组对hCG反应性均降低,睾酮生成量和cAMP含量变化一致,并与照射剂量呈线性负相关。

Mechanism of the effect of irradiation on response of Leydig cells to hCG in xitro in rats

Mechanism of the effect of different doses of X-irradiation on hCG -induced testosterone (T)secretion by Leydig cells in vitro was investigated. It was shown that hCG could significantly stimulate T and cAMP produc-ion by Leydig cells.These cells were exposed to different doses of X-irradiation at a dose-rate of 12.5 mGy/min and 0.51 Gy/min respectively after a pre-incubation for 24 h. Following irradiation, the cells were incubated in a monolayer culture with 199 medium containing hCG (0.05 IU/ml) for 48 h.For Leydig cells irradiated in low doses the response to hCG in both 25 and 50 mGy groups was significantly higher than that of the control (P<0.01) , and the cAMP content increased correspondently. For Leydig cells irradiated in large doses, however, the response to hCG was significantly inhibited in a dose-dependent manner. The T content induced by hCG diminished (r =- 0.9269),with a concomitant decrease in cAMP formation (r= - 0.8352).These results suggest that the effect of different dosages of X-irradiation on Leydig cells might be due to the corresponding changes in activity of the membrane adenylate cyclase.