Growth hormone and fertility--clinical studies

The linkage between the reproductive and somatotropic axes and the existence of a complex regulating system within the ovary involving growth factors and their binding proteins suggest that the ovary may be a target of growth hormone (GH) action. Clinical studies investigating possible applications of adjuvant GH treatment in ovulation induction and in vitro fertilization, mainly directed at poor responders to gonadotropin therapy, have shown that results are dependent on the hormonal status and 'ovarian age' of the subject. Additive GH is capable of increasing the sensitivity of ovaries to gonadotropins in those with a blatant or subtile lack of GH but not in those with a normal, saturated system. Improved pregnancy rates have not been convincingly forthcoming and more research is needed on the effect of GH and growth factors on the oocyte and endometrium. Disturbed GH kinetics in the polycystic ovary syndrome have prompted investigations of possible involvement of GH in the pathophysiology of this syndrome.