Oxytocin – a peptide serving manifold roles during the reproductive cycle in mares

Abstract

SummaryOxytocin, a peptide hormone released by the posterior pituitary, has important tasks in the reproductive biology in the mare. Functions of OT are based on its effects on smooth muscle cells of the myometrium and the myoepithelia in the mammary gland. Uterine clearance as a part of uterine defense mechanisms, delivery of the foal at parturition and milk let down in lactating mares are familiar examples. During luteolysis, oxytocin stimulates the endometrial release of prostaglandin F 2α . The consequences of the provoked secretion of oxytocin, by manipulations of the genital tract on the endocrine regulation of luteal function and on the course of the oestrous cycle are still under discussion. Furthermore, the modulating role of oxytocin on neuroendocrine events is hardly investigated in the horse up to now. Keywords:mare, oxytocin, estrous cycle, pregnancy, therapy

Influence of cycle stage, age and endometrial biopsy score on oxytocin receptor distribution and gene expression in the cervix and uterus of non-pregnant mares

“…Oxytocin is a neuropeptide hormone that is important in parturition, milk ejection and the endocrine regulation of estrus. It is also responsible for myometrial contractility, thereby facilitating fetal expulsion during parturition and post-breeding mechanical clearance of uterine contents in mares [1][2][3][4][5]. Oxytocin acts by binding to oxytocin receptors (ORs) present in various target tissues both within and outside the genital tract [1,3].…”

“…It is also responsible for myometrial contractility, thereby facilitating fetal expulsion during parturition and post-breeding mechanical clearance of uterine contents in mares [1][2][3][4][5]. Oxytocin acts by binding to oxytocin receptors (ORs) present in various target tissues both within and outside the genital tract [1,3]. In mares, radioligand-binding assays have been used to detect ORs in endometrium [6][7][8] and myometrium [8].…”