Growth hormone response to L-dopa and pyridostigmine in women with polycystic ovarian syndrome.

OBJECTIVE

To evaluate the GH secretion and clarify the factors influencing the GH secretion in women with polycystic ovarian syndrome (PCOS).

DESIGN

Comparison of the GH response to L-dopa with or without pyridostigmine (inhibitor of acetylcholinesterase) pretreatment and insulin response to oral glucose tolerance test in patients with PCOS and matched controls.

SETTING

Outpatients and healthy volunteers studied at a clinical research unit of a university hospital.

PATIENTS,

PARTICIPANTS

Ten women with PCOS and 9 controls with regular cycles were recruited.

INTERVENTIONS: After an overnight fast, each subject underwent a GH stimulation test with L-dopa with or without pyridostigmine pretreatment. Plasma insulin and glucose levels were measured after a 75-g glucose load.

MAIN OUTCOME MEASURES: Plasma GH, insulin-like growth factor I (IGF-I), insulin, and nonesterified fatty acids.

RESULTS

Growth hormone responses and GH area under the response curve (AUC) to L-dopa were significantly lower in PCOS than those in controls. Pyridostigmine enhanced the GH response to L-dopa significantly in PCOS. Insulin responses and insulin AUC to oral glucose load were significantly higher in PCOS than those in controls. Plasma IGF-I levels of PCOS were significantly higher than controls. Insulin AUC had a positive correlation with plasma IGF-I levels but an inverse correlation with GH AUC in PCOS and controls.

CONCLUSION

Our result indicated that decreased GH secretion of PCOS may be associated with a high somatostatin activity and a high plasma IGF-I level.