Tl. Horvath et al., CONTROL OF GONADOTROPIN FEEDBACK - THE POSSIBLE ROLE OF ESTROGEN-INDUCED HYPOTHALAMIC SYNAPTIC PLASTICITY, Gynecological endocrinology, 11(2), 1997, pp. 139-143
The preovulatory gonadotropin surge is a critical event in reproductio
n. Although many explanations have been given for the inhibition-disin
hibition cycle referred to as positive feedback, none are completely s
atisfactory. Recent evidence indicates that the preovulatory surge of
gonadotropin is induced, in part, by the disengagement of inhibitory s
ynaptic connections in the hypothalamic arcuate nucleus. This disinhib
ition of gonadotropin-releasing hormone secretion results in a massive
release by the estrogen-sensitized pituitary gonadotrophs. Investigat
ions are presently under way to determine whether other areas of the h
ypothalamus are involved in this estrogen-induced synaptic plasticity.