Tsubota T, Nitta H, Osawa Y, Mason J I, Kita I, Tiba T, Bahr J M
Department of Animal Sciences, University of Illinois, Urbana 61801.
J Reprod Fertil. 1994 Aug;101(3):557-61. doi: 10.1530/jrf.0.1010557.
The objective was the immunocytochemical localization of steroidogenic enzymes in the corpus luteum of Hokkaido brown bears during the period of delayed implantation. Cholesterol side-chain cleavage cytochrome P450 (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta HSD), 17 alpha-hydroxylase cytochrome P450 (P450c17) and aromatase cytochrome P450 (P450arom) were localized as biosynthetic sites of pregnenolone, progesterone, androgens, and oestrogens, respectively. Ovaries containing corpora lutea were obtained from three mature bears during the expected delayed implantation period and ovarian sections were immunostained by the avidin-biotin-peroxidase complex method using polyclonal antibodies generated against steroidogenic enzymes of mammalian origin. P450scc and 3 beta HSD were localized in all luteal cells, whereas P450c17 (0.4-5.1% of 1000 cells) and P450arom (7.1-11.2% of 1000 cells) were localized in only a few luteal cells. These data suggest that luteal cells contain steroidogenic enzymes required for progesterone synthesis but also have a minimum capability for synthesizing androgen and oestrogen during the delayed implantation period in Hokkaido brown bears.
目的是对北海道棕熊延迟着床期黄体中类固醇生成酶进行免疫细胞化学定位。胆固醇侧链裂解细胞色素P450（P450scc）、3β-羟基类固醇脱氢酶（3βHSD）、17α-羟化酶细胞色素P450（P450c17）和芳香化酶细胞色素P450（P450arom）分别被定位为孕烯醇酮、孕酮、雄激素和雌激素的生物合成位点。在预期的延迟着床期，从三只成熟熊身上获取含有黄体的卵巢，并使用针对哺乳动物来源的类固醇生成酶产生的多克隆抗体，通过抗生物素蛋白-生物素-过氧化物酶复合物法对卵巢切片进行免疫染色。P450scc和3βHSD定位于所有黄体细胞，而P450c17（每1000个细胞中的0.4 - 5.1%）和P450arom（每1000个细胞中的7.1 - 11.2%）仅定位于少数黄体细胞。这些数据表明，在北海道棕熊的延迟着床期，黄体细胞含有合成孕酮所需的类固醇生成酶，但也具有最低限度的合成雄激素和雌激素的能力。
