Saarem K, Pedersen J I
Institute for Nutrition Research, School of Medicine, University of Oslo, Blindern, Norway.
Biochem J. 1987 Oct 1;247(1):73-8. doi: 10.1042/bj2470073.
The effect of sex hormones on hydroxylation of cholecalciferol ('vitamin D3') and of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol has been investigated in female- and male-rat livers. The mitochondrial cholecalciferol 25-hydroxylase and C27-steroid 27-hydroxylase activities were respectively 4.6- and 2.7-fold higher in female- than in male-rat livers. The microsomal 1 alpha-hydroxycholecalciferol 25-hydroxylase was 2.8-fold higher in male- than in female-rat liver. No significant difference was found in the microsomal 25-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. Liver microsomes (microsomal fractions) from male, but not from female, rats also catalysed 1-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol. Injection of testosterone into female rats decreased the mitochondrial cholecalciferol 25-hydroxylase and C27-steroid 27-hydroxylase activities, but not to a statistically significant extent. Testosterone treatment had no effect on the microsomal hydroxylases in female-rat liver. Injection of oestradiol valerate to male rats resulted in increased activities of both mitochondrial hydroxylases to the same levels as those of control females, while the microsomal enzyme activities decreased. The present results indicate that sex hormones exert a regulatory control on the mitochondrial cholecalciferol 25-hydroxylase and C27-steroid 27-hydroxylase activities.
已在雌性和雄性大鼠肝脏中研究了性激素对胆钙化醇（“维生素D3”）和5β-胆甾烷-3α，7α，12α-三醇羟基化的影响。雌性大鼠肝脏中的线粒体胆钙化醇25-羟化酶和C27-类固醇27-羟化酶活性分别比雄性大鼠肝脏高4.6倍和2.7倍。雄性大鼠肝脏中的微粒体1α-羟基胆钙化醇25-羟化酶比雌性大鼠肝脏高2.8倍。在5β-胆甾烷-3α，7α，12α-三醇的微粒体25-羟基化方面未发现显著差异。雄性大鼠而非雌性大鼠的肝脏微粒体（微粒体部分）也催化5β-胆甾烷-3α，7α，12α-三醇的1-羟基化。向雌性大鼠注射睾酮会降低线粒体胆钙化醇25-羟化酶和C27-类固醇27-羟化酶活性，但在统计学上无显著差异。睾酮处理对雌性大鼠肝脏中的微粒体羟化酶无影响。向雄性大鼠注射戊酸雌二醇会使两种线粒体羟化酶的活性增加到与对照雌性相同的水平，而微粒体酶活性则降低。目前的结果表明，性激素对线粒体胆钙化醇25-羟化酶和C27-类固醇27-羟化酶活性发挥调节作用。
