Meseguer A, Catterall J F
Population Council, New York, New York 10021.
Mol Endocrinol. 1990 Aug;4(8):1240-8. doi: 10.1210/mend-4-8-1240.
Kidney androgen-regulated protein (KAP) gene expression is under androgenic control in the epithelial cells of the proximal convoluted tubule in the mouse kidney. In Tfm/Y androgen receptor-deficient mice, KAP mRNA was detected by in situ hybridization in a subpopulation of these cells only in the S3 segment of the proximal tubules in the outer medulla. Treatment of Tfm/Y animals with testosterone caused a partial induction of KAP mRNA levels, while dihydrotestosterone had no effect. These data suggested that the androgen receptor-independent induction of KAP gene expression in these animals was mediated by an estrogenic metabolite of testosterone, since dihydrotestosterone cannot be aromatized to an estrogenic form. Estrogen treatment of Tfm/Y mice caused an increase in KAP gene expression similar to that observed with testosterone. However, ovariectomy of normal female mice did not eliminate KAP gene expression in the S3 cells and, in fact, resulted in a slight increase. Adrenalectomy in combination with castration had no effect on KAP mRNA levels in S3 cells. However, hypophysectomy alone completely eliminated this cell-specific component of KAP gene expression. These results indicate that KAP gene expression is subject to cell-specific regulation in different segments of the proximal tubule and that this regulation is mediated by hormones of both gonadal and pituitary origin.
肾雄激素调节蛋白（KAP）基因表达在小鼠肾脏近端曲管的上皮细胞中受雄激素控制。在雄激素受体缺陷的Tfm/Y小鼠中，仅在外髓质近端小管的S3段，通过原位杂交在这些细胞的一个亚群中检测到KAP mRNA。用睾酮处理Tfm/Y动物可部分诱导KAP mRNA水平升高，而双氢睾酮则无作用。这些数据表明，这些动物中KAP基因表达的雄激素受体非依赖性诱导是由睾酮的雌激素代谢产物介导的，因为双氢睾酮不能芳香化为雌激素形式。用雌激素处理Tfm/Y小鼠导致KAP基因表达增加，类似于用睾酮观察到的情况。然而，正常雌性小鼠卵巢切除并未消除S3细胞中的KAP基因表达，实际上还导致了轻微增加。肾上腺切除联合去势对S3细胞中的KAP mRNA水平无影响。然而，单独垂体切除完全消除了KAP基因表达的这种细胞特异性成分。这些结果表明，KAP基因表达在近端小管的不同节段受到细胞特异性调节，并且这种调节由性腺和垂体来源的激素介导。
