Oxytocin - A peptide serving manifold roles during the reproductive cycle in mares

Abstract

Oxytocin, 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 F2α. 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.