Sholl S A
J Steroid Biochem. 1982 Feb;16(2):141-5. doi: 10.1016/0022-4731(82)90159-5.
In the rhesus monkey (Macaca mulatta) the fetal testis appears to be more active than the fetal ovary in synthesizing steroids. This occurs despite the relative abundance of potential hormone precursors in the circulation. The possibility was investigated that this discrepancy in activity may be related to the activities of two rate-limiting enzymes, estrogen synthetase (ES) and C17-20lyase (LA). ES and LA activities were characterized in monkey fetal gonads during late gestation from the rate of formation of 3H2O from [1,2-3H]-androstenedione (ES) and metabolism of [4-14C]-17-hydroxyprogesterone to [14C]-androstenedione (LA). Ovaries and testes exhibited LA activity with apparent Km values of 3.4 x 10(-6) M and 7.1 x 10(-7) M, respectively. Reaction rate was 1.8 +/- 0.3 x 10(-3) nmol/min x mg-1 protein (n = 3) in the ovary which was significantly less than LA rate in the testis (8.3 +/- 1.6 x 10(-3) nmol/min x mg-1 protein, n = 5). ES activity was detected only in the fetal ovary; it averaged 1.5 +/- 0.4 x 10(-4) nmol/min x mg-1 protein (n = 5). The apparent Km was 5.3 x 10(-8) M. Isolation of the [3H]-estrogens formed revealed the synthesis of estrone and estradiol-17 beta. During the 30 min incubation the amount of 3H2O synthesized diverged from the combined quantity of tritiated reason fetal ovarian synthetic capacity is lower than that of the testis may be due to a low level of LA and ES activity in the ovary and additional metabolism of estrone and estradiol-17 beta.
在恒河猴（猕猴）中，胎儿睾丸在合成类固醇方面似乎比胎儿卵巢更活跃。尽管循环中潜在激素前体相对丰富，但仍出现这种情况。研究了这种活性差异可能与两种限速酶，即雌激素合成酶（ES）和C17-20裂解酶（LA）的活性有关的可能性。在妊娠后期，通过[1,2-3H]-雄烯二酮形成3H2O的速率（ES）以及[4-14C]-17-羟孕酮代谢为[14C]-雄烯二酮的速率（LA），对猴胎儿性腺中的ES和LA活性进行了表征。卵巢和睾丸均表现出LA活性，其表观Km值分别为3.4×10^(-6)M和7.1×10^(-7)M。卵巢中的反应速率为1.8±0.3×10^(-3)nmol/分钟×mg^(-1)蛋白质（n = 3），明显低于睾丸中的LA速率（8.3±1.6×10^(-3)nmol/分钟×mg^(-1)蛋白质，n = 5）。仅在胎儿卵巢中检测到ES活性；其平均为1.5±0.4×10^(-4)nmol/分钟×mg^(-1)蛋白质（n = 5）。表观Km为5.3×10^(-8)M。对形成的[3H]-雌激素进行分离，揭示了雌酮和雌二醇-17β的合成。在30分钟的孵育过程中，合成的3H2O量与氚化产物的总量不同，胎儿卵巢的合成能力低于睾丸可能是由于卵巢中LA和ES活性水平较低以及雌酮和雌二醇-17β的额外代谢。
