Circulating Concentrations of Estradiol, Luteinizing Hormone, and Follicle-Stimulating Hormone during Waves of Ovarian Follicular Development in Prepubertal Cattle(1)

Prepubertal Cattle(1)

Ovariectomy of prepubertal cattle results in an increase in frequency of release of LH pulses. This post-ovariectomy increase in frequency of LH pulses can be inhibited by administration of estradiol. The number of receptors for estradiol in the medial basal hypothalamus decreases prepuberty, and this decrease may result in the decreased negative feedback of estradiol on release of LH pulses. Thus there is thought to be a change in sensitivity to estradiol due to decreased receptors at the hypothalamus in prepubertal cattle, with estradiol produced by ovarian follicles regulating secretion of LH by inhibiting the putative hypothalamic pulse generator for LHRH. Consequently, frequency of release of LH pulses increases between 50 days prepuberty and onset of puberty.

Prepubertal cattle have waves of ovarian follicular development similar to those observed in postpubertal cattle. Associated with these waves of ovarian follicular development are changes in diameter of dominant follicles and of largest subordinate follicles. As with postpubertal female cattle, increases in concentrations of FSH in blood plasma have been reported to precede emergence of waves of follicular development in prepubertal cattle.

This entry was posted in Hormone and tagged Estradiol, Follicle-Stimulating Hormone, Luteinizing Hormone, Ovarian.