Arai K, Komura H, Akikusa T, Iio K, Kishi H, Watanabe G, Taya K
Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Fuchu, Japan.
Biol Reprod. 1997 Jun;56(6):1482-9. doi: 10.1095/biolreprod56.6.1482.
To examine the contributions of endogenous inhibin and estradiol to the regulation of FSH and LH secretion in the pregnant rat, some rats were passively immunized against inhibin and/or estradiol, and others were ovariectomized, on Days 5, 10, 15, and 20 of pregnancy. Ovarian and uterine venous blood was collected separately to confirm the sources of inhibin and steroid hormones during pregnancy. Immunoreactivity of inhibin in the placenta was also examined by RIA. Levels of inhibin in ovarian venous plasma were significantly higher than those in peripheral plasma during pregnancy. No difference was observed between the levels of inhibin in uterine venous plasma and peripheral plasma. No immunoreactivity of inhibin was detected in placental homogenate from rats at Days 10, 15, and 20. FSH secretion significantly increased after immunoneutralization of inhibin during pregnancy. A marked increase in FSH secretion was noted on Days 5 and 20, and the smallest increase was observed on Day 15. Administration of estradiol antiserum (AS) alone did not induce a significant increase in FSH secretion on any day of pregnancy. However, a synergistic effect of estradiol AS and inhibin AS was observed on Day 20. On Days 5, 10, and 20, administration of inhibin AS or estradiol AS induced a significant increase in LH secretion. A synergistic effect of inhibin AS and estradiol AS on LH secretion was observed on Day 5. On Days 5 and 10, significantly high LH secretion was noted in ovariectomized rats as compared with that in rats treated with both inhibin AS and estradiol AS, indicating that other ovarian hormones such as progesterone may be involved in the suppression of LH secretion in these stages of pregnancy. These data indicate that both inhibin and estradiol, predominantly secreted from the ovary, are involved in the regulation of gonadotropin secretion during pregnancy as during the estrous cycle in the rat.
为研究内源性抑制素和雌二醇对妊娠大鼠促卵泡激素（FSH）和促黄体生成素（LH）分泌调节的作用，在妊娠第5、10、15和20天，对部分大鼠进行抑制素和/或雌二醇的被动免疫，对其他大鼠进行卵巢切除。分别采集卵巢和子宫静脉血，以确定妊娠期间抑制素和甾体激素的来源。同时用放射免疫分析法（RIA）检测胎盘组织中抑制素的免疫反应性。妊娠期间，卵巢静脉血浆中抑制素水平显著高于外周血浆。子宫静脉血浆和外周血浆中抑制素水平无差异。在妊娠第10、15和20天的大鼠胎盘匀浆中未检测到抑制素的免疫反应性。妊娠期间抑制素免疫中和后，FSH分泌显著增加。在第5天和第20天观察到FSH分泌显著增加，第15天增加最少。单独给予雌二醇抗血清（AS）在妊娠的任何一天均未引起FSH分泌显著增加。然而，在第20天观察到雌二醇AS和抑制素AS有协同作用。在第5、10和20天，给予抑制素AS或雌二醇AS均可引起LH分泌显著增加。在第5天观察到抑制素AS和雌二醇AS对LH分泌有协同作用。在第5天和第10天，卵巢切除大鼠的LH分泌显著高于同时给予抑制素AS和雌二醇AS的大鼠，这表明在妊娠的这些阶段，其他卵巢激素如孕酮可能参与了LH分泌的抑制。这些数据表明，主要由卵巢分泌的抑制素和雌二醇在大鼠妊娠期间对促性腺激素分泌的调节作用与发情周期时相似。
