Objective: To test the hypothesis that anovulation and infertility in women is associated with an impaired secretory capacity for growth hormone (GH).
Design: Comparison of the hormonal and metabolic response to two GH stimulation tests in a patient group and in a control group.
Setting: Outpatients and healthy volunteers studied at a clinical research unit of a university hospital.
Patients, participants: 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.
Interventions: 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.
Main outcome measures: Serum GH, insulin-like growth factor I (IGF-I), insulin and non-esterified fatty acids (NEFA).
Results: 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.
Conclusions: Relative GH insufficiency seems to be present in these patients, but the clinical significance of this finding remains to be elucidated.