Aromatase and Estrogen 2-Hydroxylase Activities of Human Placental Microsomes in Pregnancy-Induced Hypertension

Endocrine Journal

KAZUTOSHI OKUBO¹  MASATOSHI JINBO¹  YOSHIRO TOMA¹  YUKIKO SHIMIZU¹  TAKUMI YANAIHARA¹ 

[1] Department of Obstetrics and Gynecology, Showa University School of Medicine

关键词: Human placenta;    Aromatase;    Estrogen 2-hydroxylase;    Pregnancy-induced hypertension;   

DOI  :  10.1507/endocrj.43.363

学科分类：内分泌与代谢学

来源: Japan Endocrine Society

【 摘 要 】

References(27)Cited-By(4)2-Hydroxylation is one of the major metabolic pathways of estrogens and is believed to be catalyzed by a form of cytochrome P450. Recently it has been reported that estrogen 2-hydroxylase activity in human placenta is catalyzed by aromatase. Some investigators suggested the effect of catechol estrogen on human placental steroidogenesis which may be related to pregnancy-induced hypertension (PIH) through the inhibition of catechol-O-methyltransferase (COMT) activity. In order to better understand the interrelationship between placental aromatase and estrogen 2-hydroxylase activities in PIH patients, both activities were evaluated in the PIH placentas. Human placental microsomes obtained from PIH patients were incubated with [1β-3H]androstenedione or [2-3H]estradiol in the presence of NADPH. Aromatase and estrogen 2-hydroxylase activities were assessed by the tritium water method. The immunosuppression patterns of both activities due to monoclonal anti-aromatase cytochrome P450 antibody (MAb3-2C2) were studied. Estrogen 2-hydroxylase activity was significantly higher in PIH placentas (4.7± 0.9pmol/min/mg protein, n=7) than in normal placentas (3.0 ±0.7pmol/min/mg protein, n=7). When the PIH placental microsomes were subjected to immunosuppression by 1 to 100μg IgG of MAb3-2C2, estrogen 2-hydroxylase activity was suppressed by 94 to 65% whereas aromatase activity was strongly suppressed by 72 to 17%, respectively. From our results of high estrogen 2-hydroxylase activity in PIH placentas, it is assumed that there is a different estrogen catalyzing mechanism in PIH placentas.

【 授权许可】

Unknown