ラットおよびヒト精巣hCGレセプターのhCGによるdown-regulation

Abstract

1) hCG投与後, ラットおよびヒト精巣hCG receptorが7日間および5日間, それぞれ有意に減少した.2)このhCG receptorの減少はbinding sitesのhCGによるoccupancyのみならず, down-regulationなど他のメカニズムに起因すると推測された.3)器管培養を用いたin vitroの実験結果はin vivoの実験結果と相似していた.よって精巣器管培養法は精巣機能のホルモン制御などの研究に有用で, 特にin vivoの実験が比較的行い難いヒト精巣に関する研究に有力な手段である

Changes in rat and human testicular human chorionic gonadotropin (hCG) binding sites induced by hCG were estimated in vivo and in vitro. After a single administration of hCG, the specific hCG binding sites were significantly reduced for 7 and 5 days in rat and human testes, respectively. However, hCG binding sites had recovered to pretreatment values by the 14th day after the administration. Occupied hCG binding sites measured in both rat and human testes accounted for about half of the reduced binding sites on the day after administration of hCG, but thereafter the number of sites occupied was not correlated with the reduction of the binding induced a dose-related significant loss of the specific hCG binding sites for 7 and 5 days in rat and human testes, respectively. Thereafter, the number of binding sites gradually increased. These patterns of change in hCG binding sites in vitro were similar to those in vivo. These findings suggest that the reduction in hCG binding sites in rat and human testes by hCG is due not only to occupancy but also down-regulation of the binding sites. In conclusion, the present testicular organ culture method is useful to study hormonal regulation of testicular function, especially in human testes.