The equine placenta and equine chorionic gonadotrophin--an overview.

H O Hoppen
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引用次数: 24

Abstract

Chorionic gonadotrophins seem to be unique for primate and equid species. Unlike primates, the equine conceptus does not implant in the maternal uterine endometrium until around day 37 of pregnancy. At this time specialized cells of the trophoblast, organized in the embryonic girdle, invade the endometrium and become established in the endometrial stroma, forming the so-called endometrial cups. This migration of girdle cells is accompanied by their morphological transformation into large decidual-like cells and by the appearance of a gonadotrophic hormone in the mare's blood. There is convincing evidence today that the hormone is of chorionic origin; therefore the term equine Chorionic Gonadotrophin (eCG) seems to be more appropriate than the formerly used term Pregnant Mare Serum Gonadotrophin (PMSG). Secretion of eCG peaks between days 60 and 80 in pregnant mares, to decline gradually until day 130 of gestation, with pronounced inter-individual variation. There appear to be no hormonal regulatory mechanisms controlling eCG synthesis and secretion, suggesting that the size and the morphology of the endometrial cups are the limiting factors. Equine CG is a glycoprotein hormone, composed of noncovalently bound alpha- and beta-subunits. The alpha-subunit consists of 96 amino acids and is identical for eCG and the pituitary hormones eLH, eFSH, and eTSH. The beta-subunit is similar to beta-hCG in that both have a C-terminal extension. It is comprised of 149 amino acids and the peptide primary structure is identical to that of beta-eLH.(ABSTRACT TRUNCATED AT 250 WORDS)

马胎盘和马绒毛膜促性腺激素——综述。
绒毛膜促性腺激素似乎是灵长类动物和马科动物特有的。与灵长类动物不同,马的母体直到怀孕第37天左右才会植入母体子宫内膜。此时,在胚胎带组织起来的滋养细胞的特化细胞侵入子宫内膜,并在子宫内膜间质中建立起来,形成所谓的子宫内膜杯。这种腰带细胞的迁移伴随着它们的形态转变为大的蜕膜样细胞,并伴随着马血液中促性腺激素的出现。如今有令人信服的证据表明,这种激素是绒毛膜起源的;因此,术语马绒毛膜促性腺激素(eCG)似乎比以前使用的术语妊娠母马血清促性腺激素(PMSG)更合适。妊娠母马心电图分泌在妊娠第60 ~ 80天达到峰值,至妊娠第130天逐渐下降,个体间差异明显。似乎没有激素调节机制控制心电图的合成和分泌,这表明子宫内膜杯的大小和形态是限制因素。马CG是一种糖蛋白激素,由非共价结合的α和β亚基组成。α -亚基由96个氨基酸组成,与eCG和垂体激素eLH、eFSH和eTSH相同。β -亚基与β - hcg相似,两者都有c端延伸。它由149个氨基酸组成,肽一级结构与β - elh相同。(摘要删节250字)
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