The role of growth hormone in ovulation induction.

During the last few years the potential importance of intraovarian regulators of follicular development has been recognized, and the effects of various growth factors on granulosa cell responses to gonadotrophins have been extensively investigated. Ovarian responses to exogenous gonadotrophins were improved by adjuvant growth hormone (GH) treatment of GH-deficient patients, and responses to hMG were apparently predicted by estimated GH reserve. However, the results of different studies of GH/hMG cotreatment were equivocal. Therefore, a randomized, prospective, cross-over study protocol between GH/hMG/hCG versus hMG/hCG was undertaken. Whereas 16 pregnancies were achieved in the 26 Clonidine-negative patients (61.5%) either in the GH/hMG cycle (11) or in the succeeding one (5), no benefit was detected in 8 Clonidine-positive patients from the GH/hMG combination. The recently described GH-binding protein (BP) may reflect the GH-receptor. GH-BP levels were evaluated in the sera and follicular fluids (FF) of patients undergoing ovulation induction with either hMG/hCG or GH/hMG/hCG. GH-BP increase in serum correlated with E2, and progesterone (P4) concentrations. The FF GH-BP correlated with serum GH-BP levels. Lower FF GH-BP levels were measured in older compared to younger women, while increased values were obtained both in patients with elevated E2 concentrations in serum and in FF, or when more than five oocytes were retrieved. Primary increased GH-BP in unexplained infertility may suggest a new mechanism whereby excessive GH-BP levels may deprive GH from its receptor and thus decrease the introavarian IGF-I production.(ABSTRACT TRUNCATED AT 250 WORDS)