Identification and cellular localization of growth hormone receptor gene expression in the human ovary

While in vivo and in vitro studies in rodents, pigs and women suggest that growth hormone (GH) can stimulate ovarian steroidogenesis, it is not known if this effect is mediated by a direct action on the ovary. The absence of GH receptor (GHR) messenger RNA would mitigate against a direct ovarian effect. We used the reverse transcriptase-polymerase chain reaction and in situ hybridization to examine whether the GHR mRNA was present in homogenates of seven human ovaries or in tissue sections of ten ovaries. GHR gene expression was detected in PCR products after Southern blot hybridization using an oligoprobe directed to the intracellular domain sharing no homology to the prolactin receptor. In situ hybridization using the same digoxigenin-labeled oligoprobe localized the GHR mRNA in the granulosa cells of dominant and antral follicles, corpus luteum, corpora albicans and the endothelium of blood vessels. GHR mRNA was not detected in preantral follicles, theca interna, theca externa, oocytes, or stroma. The presence of GHR mRNA in human granulosa cells and corpus luteum, taken together with previous studies showing GH-induced stimulation of estradiol and progesterone secretion, suggest that GH may play a direct role in the development of the human follicle.