In vivo action of activin-A on pituitary-gonadal system.
In vivo action of activin-A on pituitary-gonadal system.
复制标题
激活素 A 对垂体-性腺系统的体内作用。
作者：
M. Doi;M. Igarashi;Y. Hasegawa;Y. Eto;H. Shibai;T. Miura;Y. Ibuki
激活素是抑制素β亚基的二聚体，已被发现能刺激培养的垂体细胞分泌FSH。然而，激活素在体内的作用尚不清楚。未成熟雌性大鼠每日皮下注射激活素A 40微克，持续1-3天，可引起血清FSH、抑制素、雌二醇、子宫重量和卵巢FSH受体显著增加。每天皮下注射激活素-A 5微克或20微克，连续6天，可引起卵巢重量显著增加和大卵泡的发育。然而，每天皮下注射20微克激活素-A给去垂体的未成熟雌性大鼠连续3天，对卵巢和子宫重量、血清抑制素、雌二醇和孕酮水平没有明显的影响。与同时注射赋形剂和PMSG相比，同时注射激活素A和5IU PMSG可显著增加去垂体未成熟雌性大鼠的卵巢和子宫重量、血清抑制素和雌二醇水平。这些结果表明，激活素A不仅能引起垂体FSH分泌的增加，而且还能直接引起卵巢的自分泌或旁分泌刺激，使卵巢FSH受体数目增加，卵巢和子宫重量增加，卵巢分泌的抑制素和雌二醇水平增加。
Activin, a dimer of the beta-subunits of inhibin, has been found to stimulate FSH secretion from the cultured pituitary cells. However, in vivo action of activin is poorly elucidated. Daily sc injections of 40 micrograms activin-A over a period of 1-3 days to intact immature female rats caused a significant increase in serum FSH, inhibin, estradiol, uterine weight, and ovarian FSH receptors. Daily sc injections of 5 micrograms or 20 micrograms activin-A for 6 days caused a marked increase in ovarian weight and the development of large ovarian follicles. However, daily sc injections of 20 micrograms activin-A to hypophysectomized immature female rats for 3 days induced no significant changes in ovarian and uterine weight, serum inhibin, estradiol, and progesterone levels. Simultaneous injections of both activin-A and 5 IU PMSG induced a significant increase in ovarian and uterine weight, serum inhibin, and estradiol levels, compared to simultaneous injections of both vehicle and PMSG in the hypophysectomized immature female rats. These results demonstrate that activin-A induces not only an increase of FSH secretion from the pituitary but also a direct autocrine or paracrine ovarian stimulation resulting in an increase of the number of ovarian FSH receptors and ovarian and uterine weight, as well as an increase in the level of inhibin and estradiol secretion from the ovary.