Hormonal regulation of LH receptor mRNA and expression in the rat ovary.

Agonist-induced changes in expression and mRNA levels of luteinizing hormone (LH) receptors were compared during stimulation of ovarian follicular maturation and luteinization by gonadotropic hormones. Three major species of LH receptor mRNA, 5.8, 2.6 and 2.3 kb, were present throughout differentiation and changed similarly, the 5.8 kb species being consistently more abundant than the smaller forms. The increased expression of plasma-membrane LH receptors in preovulatory follicles and luteinized ovaries and their homologous down-regulation during follicular and luteal desensitization were closely correlated with the steady-state receptor mRNA levels. The reappearance of LH receptors following desensitization during the luteal stage was preceded by an increase in mRNA levels. These studies have demonstrated that the expression of LH receptors during follicular maturation, ovulation and desensitization is related to the prevailing levels of receptor mRNA in the ovary.