Imataka H, Suzuki K, Inano H, Kohmoto K, Tamaoki B
Department of Animal Breeding, Faculty of Agriculture, University of Tokyo, Japan.
Gen Comp Endocrinol. 1988 Feb;69(2):153-62. doi: 10.1016/0016-6480(88)90001-9.
The left ovary and testis of 15-day-old embryos of the chicken were compared in the enzyme activities related to steroidogenesis. The activity of delta 5-3 beta-hydroxysteroid dehydrogenase coupled with delta 5-delta 4 isomerase in the ovary was similar to that of the testis. Activities of 17 alpha-hydroxylase and C-17-C-20 lyase in the ovary were 2.5 and 2.6 times those in the testis. From the CO-induced difference spectrum, the content of cytochrome P-450 in the ovarian microsomes was estimated as 27.6 pmol/mg protein. However, no detectable amount of cytochrome P-450 was observed in the testicular microsomal fraction. The substrate (progesterone)-induced difference spectrum was appreciable only in the ovarian microsomes. The activity of microsomal NADPH-cytochrome c reductase in the ovary was significantly higher than that in the testis. The activities of 17 beta-hydroxysteroid dehydrogenase in both gonads were similar to each other, when androstenedione was used as substrate. However, its activity in the ovary was 1.4 and 3.1 times that in the testis, when dehydroepiandrosterone and estrone were used as substrate, respectively. Aromatase activity in the ovary was over 100 times that in the testis, as assessed by release of [3H]water from [1-3H]testosterone. Appreciable amounts of radioactive estradiol-17 beta and estrone were formed from [4-14C]testosterone and [7-3H]androstenedione, respectively, only by the ovarian tissue. 5 beta-Reductase activity in the ovary was 1.4 times that in the testis.
对15日龄鸡胚胎的左卵巢和睾丸中与类固醇生成相关的酶活性进行了比较。卵巢中δ5-3β-羟基类固醇脱氢酶与δ5-δ4异构酶的活性与睾丸中的相似。卵巢中17α-羟化酶和C-17-C-20裂解酶的活性分别是睾丸中的2.5倍和2.6倍。根据一氧化碳诱导的差光谱，估计卵巢微粒体中细胞色素P-450的含量为27.6 pmol/mg蛋白质。然而，在睾丸微粒体部分未观察到可检测量的细胞色素P-450。底物（孕酮）诱导的差光谱仅在卵巢微粒体中明显。卵巢中微粒体NADPH-细胞色素c还原酶的活性显著高于睾丸中的。当以雄烯二酮为底物时，两性中17β-羟基类固醇脱氢酶的活性彼此相似。然而，当分别以脱氢表雄酮和雌酮为底物时，其在卵巢中的活性分别是睾丸中的1.4倍和3.1倍。通过[1-3H]睾酮释放[3H]水评估，卵巢中的芳香化酶活性是睾丸中的100多倍。仅卵巢组织能分别由[4-14C]睾酮和[7-3H]雄烯二酮形成可观量的放射性雌二醇-17β和雌酮。卵巢中5β-还原酶的活性是睾丸中的1.4倍。
