INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS IN SERUM AND FOLLICULAR-FLUID FROM WOMEN UNDERGOING OVARIAN STIMULATION WITH AND WITHOUT GROWTH-HORMONE

The effects of supplementary growth hormone (GH) upon insulin-like growth factor binding proteins (IGFBP) in serum and ovarian follicular fluid were investigated in women undergoing buserelin-human menopausal gonadotrophin (HMG) ovulation induction for in-vitro fertilization. IGFBPs were detected by Western ligand blotting (WLB) or radioimmunoassay (IGFBP-3) and were shown in the present study to increase and decrease in patients with diseases of GH excess or deficiency. In the women undergoing treatment for ovulation induction, radioimmunoassay of IGFBP-3 gave results which were consistent with the well-documented C;H dependency of this protein, increasing in the serum when GH was administered at the same time as buserelin-HMG. In contrast there were no consistent patterns in the abundance of the IGFBPs in serum and follicular fluid examined by WLB whether or not the patient was receiving GH, and the IGFBPs varied independently of the result obtained by radioimmunoassay. Other studies have shown that during pregnancy a serum protease can dramatically decrease the detection of the IGFBPs on the WLB. However, there was no evidence for a protease in the serum or follicular fluid from these nonpregnant women undergoing ovulation induction. Tissue availability of IGFs is probably regulated by the BPs, so that data would suggest that in normal women, neither ovarian activity nor GH at pharmacological concentrations is the primary regulator of the IGFBPs, which are likely to be regulated by some other factor(s), e.g. nutrition. These data may account for the lack of consistent clinical improvement in studies investigating the hypothesis that supplementary GH during ovulation induction with gonadotrophins would be beneficial.