Ghosh D K, Dunham W R, Sands R H, Menon K M
Endocrinology. 1987 Jul;121(1):21-7. doi: 10.1210/endo-121-1-21.
The locus of gonadotropin-induced acute stimulation of pregnenolone production by cholesterol side-chain cleavage (CSCC) enzyme containing cytochrome P450 (cytP450scc) was examined in rat corpus luteum. Mitochondria were isolated from pseudopregnant rat ovaries after treatment with different doses of human CG (hCG) (25-200 IU) for 30 min; Electron Paramagnetic Resonance (EPR) spectra of high spin cholesterol complex of cyt P450scc (type I high spin EPR signal) and the cyt P450scc activity were determined. hCG treatment increased the formation of type I EPR spectra compared to that obtained with saline-treated controls, and pretreatment with cycloheximide (30 mg/kg BW) before hCG abolished this increase. The magnitude of type I EPR signal diminished with increasing pH over the range of 6.2-7.3. The type I EPR signal increased with doses of hCG and correlated well with the pregnenolone production. Aminoglutethimide treatment (competitive inhibitor of CSCC) before hCG injection led to an increased accumulation of cholesterol in inner mitochondrial membranes with a corresponding decrease in the outer membrane cholesterol, and cycloheximide treatment inhibited this accumulation. This suggests that the transport of cholesterol to inner mitochondrial membranes from outer membranes is regulated by hCG. In addition, gonadotropin also regulates the redistribution of cholesterol within the inner mitochondrial membranes.
在大鼠黄体中研究了促性腺激素诱导含细胞色素P450（细胞色素P450scc）的胆固醇侧链裂解（CSCC）酶急性刺激孕烯醇酮生成的位点。用不同剂量的人绒毛膜促性腺激素（hCG）（25 - 200 IU）处理假孕大鼠卵巢30分钟后，分离线粒体；测定细胞色素P450scc的高自旋胆固醇复合物的电子顺磁共振（EPR）光谱（I型高自旋EPR信号）和细胞色素P450scc活性。与盐水处理的对照组相比，hCG处理增加了I型EPR光谱的形成，并且在hCG之前用环己酰亚胺（30 mg/kg体重）预处理消除了这种增加。在6.2 - 7.3的pH范围内，I型EPR信号的强度随pH升高而降低。I型EPR信号随hCG剂量增加而增加，并且与孕烯醇酮生成密切相关。在注射hCG之前用氨鲁米特处理（CSCC的竞争性抑制剂）导致线粒体内膜中胆固醇积累增加，外膜胆固醇相应减少，并且环己酰亚胺处理抑制了这种积累。这表明hCG调节胆固醇从外膜向内线粒体膜的转运。此外，促性腺激素还调节线粒体内膜内胆固醇的重新分布。
