Ovarian hormones and their role in oestrous cycle in animals: A review

Abstract

Ovarian hormones play a central role in successful reproduction in the female animal and they principally act by their feedback effects in the hypothalamo-hypophyseal-ovarian axis to coordinate various events in reproduction. The ovary produces both steroid and nonsteroid hormones and other substances. The steroid hormones have important role in expression of estrus, feedback control of gonadotrophin secretion, follicular development and ovulation. Estrogen mainly has positive feedback during follicular phase and in causing preovulatory gonadotrophin surge and progesterone mainly a negative feedback on LH secretion during the luteal phase. The peptide hormones, especially the inhibins, along with estrogens play a significant role in control of follicular development through regulation of FSH secretion. An understanding of their role and mechanism of action, types and expression of their receptors in various target organs has facilitated use of these hormones, their analogues, antagonists in control and manipulation of events during oestrous cycle-the estrus, folliculor development. gonadotrophin secretion and ovulation.