Growth hormone secretory capacity and serum insulin-like growth factor I levels in primary infertile, anovulatory women with regular menses

Abstract

To test the hypothesis that anovulation and infertility in women is associated with an impaired secretory capacity for growth hormone (GH). Comparison of the hormonal and metabolic response to two GH stimulation tests in a patient group and in a control group. Outpatients and healthy volunteers studied at a clinical research unit of a university hospital. Eight infertile, anovulatory women (luteal phase serum progesterone [P] less than 25 nmol/L) with regular cyclic bleeding. Eight age- and body mass index-matched healthy volunteers with luteal phase serum P levels greater than 25 nmol/L. After an overnight fast, each subject underwent a standardized GH stimulation test composed of sequential arginine infusion and heat exposure on days 5 to 8 of the menstrual cycle. Serum GH, insulin-like growth factor I (IGF-I), insulin and non-esterified fatty acids (NEFA). Serum GH increased in both groups but was significantly lower in the study group (P less than 0.03). No difference was found in the circulating levels of IGF-I, insulin, and NEFA. Relative GH insufficiency seems to be present in these patients, but the clinical significance of this finding remains to be elucidated.