Expression of functional growth hormone receptors in human granulosa cells

Abstract

Both clinical and experimental evidence suggest that growth hormone may be of importance for ovarian function. The present study investigated whether growth hormone receptors are expressed in human granulosa cells. Granulosa cells were isolated either from natural cycles or from stimulated cycles in the course of in-vitro fertilization. Total RNA hybridized with a 32P-labelled rat growth hormone receptor cRNA probe revealed one major transcript with an estimated size of 4.5 kb and one minor transcript with an estimated size of 1.3 kb. Biotinylated growth hormone was used to analyse growth hormone binding. Competitive growth hormone binding was detected in freshly isolated granulosa cells, as well as in cultured cells. Growth hormone augmented basal and/or follicle stimulating hormone-stimulated steroidogenesis in granulosa cells obtained from patients with natural cycles, but the response to growth hormone stimulation showed considerable variation. We conclude that functional growth hormone receptors are present in human granulosa cells and that growth hormone, therefore, may have an important role in ovarian function.

Comparison of Growth Hormone and Insulin-Like Growth Factor-I Regulation of Estradiol and Progesterone Production in Human Luteinized Granulosa Cells

“…There are suggestions that granulosa cells from follicles obtained during surgical oophorectomy or during natural cycle oocyte retrieval may be more responsive to GH than are cells obtained from women undergoing exogenous gonadotropin administration (8,23). This seems unlikely in that the cells retrieved in our study exhibit similar magnitude of GH response with FSH as seen in other studies.…”

“…(8), the combination of GH and FSH increases estradiol production more than does FSH alone. Even though the results observed in our study were inconsistent, the combination of our data with other reports suggests that GH could play a modest role in enhancing FSH action in granulosa cells.…”

“…IGF-I has been shown to augment gonadotropin stimulation of steroidogenesis in human gran ulosa cells (7). GH, however, may be able to stimulate ovaria n development or steroidogenesis directly, because GH receptors have been demonstrated in the human ovary (8), and, in animal studies, GH treatment increases steroidogenesis and gonadotropin receptor development (9,10).…”

Effect of sequential medium on in vitro culture of goat ovarian cortical tissue

“…GH has been shown to play a role in folliculogenesis through the detection of GH-R immunoreactivity and mRNA encoding GH-R in ovarian tissue in humans (Carlsson et al, 1992) and cows (Kölle et al, 1998). Some in vitro studies suggest that GH plays a role in follicular growth during the early gonadotropin-independent stages of folliculogenesis and could have a direct inhibitory action on follicle apoptosis Hsueh, 1998 andSirotkin andMakarevich, 1999).…”

Clinical utility of adjuvant growth hormone in the treatment of patients with polycystic ovaries undergoing in vitro fertilization

“…Moreover, the presence of functional GH receptors in human granulosa cells, in spontaneous and stimulated cycles, has been demonstrated (14), supporting a role for GH in enhancing FSH-stimulated E2 production. A further direct effect in vitro of GH on granulosa cell differentiation, which seems to be mediated, at least in part, by the autocrine action of IGFs, particularly IGF-II, has recently been demonstrated (8).…”