Modulation of the steroidogenesis of cultured human granulosa-lutein cells by gonadotropin-releasing hormone analogs.

GnRH analogs are widely used in reproductive medicine to create a hypogonadotropic hypogonadism. However, numerous animal studies have demonstrated a direct regulation of the gonadal function by GnRH. To ascertain this direct ovarian effect in humans, the steroidogenesis of cultured human granulosa cells was studied with or without GnRH and five of its agonists. Buserelin (D-Ser(But)6, desGly10) GnRH ethylamide, leuprorelin (D-Leu6, desGly10) GnRH ethylamide, H4055 (desGly10) GnRH ethylamide, and H4065 (D-Trp6, desGly10) GnRH ethylamide significantly enhanced estradiol secretion. In addition, buserelin induced a significant cell surface decrease that seemed to be mediated by cytoskeleton modifications. The two other molecules, GnRH and triptorelin (D-Trp6) GnRH), had no effect on estrogen secretion at any of the studied concentrations. Thus, despite similar pituitary effects, these agonists did not exhibit the same ovarian action. This may be accounted for by the differences found between pituitary and ovarian receptors. These results suggest that some GnRH analogs can modulate human granulosa cell steroidogenesis at least in the preovulatory period.

Culture of human preovulatory granulosa cells: effect of extracellular matrix on steroidogenesis.

Human luteal granulosa cells, harvested from preovulatory follicles during in vitro fertilization attempts, were cultured in a serum-precoated substratum ('serum cells') or on a collagen matrix ('collagen cells'). Concerning the 'serum cell' model, E2 secretion was very low in the absence of androgen; when androstenedione was added to the culture medium, cells secreted 180 +/- 52 pmol/ml/24 h of estradiol, 440 +/- 78 pmol/ml/24 h of testosterone and lower quantities of estrone and estriol. Follicle stimulating hormone induced a significant increase in estradiol and estriol, while the secretion of the other steroids was not altered. The secretion of progesterone was 3.15 +/- 1 nmol/ml/24 h and significantly enhanced by luteinizing hormone (+ 95%; P < 0.01). The secretions of 17 alpha-hydroxyprogesterone and 20 alpha-dihydroprogesterone were low and not modified by luteinizing hormone. 'Collagen cells', in basal conditions, showed an increased secretion of estradiol (+ 50%, P < 0.05), became rounded and were less responsive to gonadotropins when compared with 'serum cells'. Thus, the use of a collagen matrix, similarly to gonadotropins, stimulated granulosa cell steroidogenesis in relation to modifications of cell shape. The higher responsiveness of serum cells to gonadotropins makes this model more suitable for physiological and pharmacological studies than the collagen one.