Pattern of Ovarian Progestin Secretion and Cholesterol Content in the Rat with 5-day Estrous Cycle

概要

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A majority of the female Holtzman rats bred in our laboratory, under controlled illumination for 14 hr daily (5:00-19:00), exhibited regular 5-day estrous cycle in which 2 days of vaginal cornification (E I and E II) were followed by 2 days of leucocytic smear (D I and D II) and 1 day of vaginal proestrus (PE). The preovulatory excitation of hypothalamus occurred between 15:00 and 18:00 on E I and ovulation followed around 2:00-4:30 on E II. Progesterone in ovarian venous blood fluctuated showing two peaks; a lesser peak in the late afternoon of E I (preovulatory peak) and greater peak on D II (postovulatory peak). The former peak was greater than the latter by 1.4-fold, which contrasted with the secretion pattern found in 4-day cyclic rat. 20α-hydroxypregn-4-en-3-one in the blood also showed two peaks; one early on E I and the other during the days of D I and D II. Ovarian contents of esterified choresterol were inversely correlated with the levels of total progestin in the ovarian venous blood, and an increased progestin synthesis is supposed to occur primarily at expence of ovarian stores of cholesterol, presumably esterified form.
北里大学の論文
1980-12-31