[Gene expression of gonadotropin releasing hormone in the rat ovary].

Although there have been several reports indicating the existence of GnRH or GnRH-like substance in the rat ovary, its synthesis as well as its physiological role in the ovary still remains unknown. In the present study, GnRH mRNA in the rat ovary was examined by using a cRNA probe complementary to the gene of the rat GnRH. The hybridizing band of 700bp was found in the extract from the rat ovary by northern blotting with 32P-labeled GnRH cRNA. In situ hybridization with 35S-labeled cRNA revealed that the site of synthesis of GnRH was granulosa cells and its synthesis was stimulated by the administration of PMSG. These results suggest that GnRH is synthesized in the rat ovary and may play a role in the local regulation of ovarian function.