Metformin administration modulates and restores luteinizing hormone spontaneous episodic secretion and ovarian function in nonobese patients with polycystic ovary syndrome

Abstract

Objective: To evaluate the effects of metformin administration on spontaneous LH episodic release in a group of nonobese polycystic ovary (PCOS) patients.

Design: Controlled clinical study.

Setting: PCOS patients in a clinical research environment.

Patient(s): Twenty nonobese PCOS patients were enrolled after informed consent.

Intervention(s): All patients underwent hormonal evaluations and a pulsatility study (sampling every 10 minutes for 4 hours) before and at the sixth month of therapy (metformin, 500 mg, p.o. b.i.d.). Ultrasound examinations and Ferriman-Gallwey scoring were also performed.

Main outcome measure(s): Measurements of plasma LH, FSH, estradiol (E(2)), androstenedione (A), 17-hydroxy-progesterone (17-OHP), and testosterone (T), glucose, insulin, and C-peptide concentrations.

Result(s): After 6 months of metformin administration, the plasma LH, 17-OHP, A, and T levels and LH/FSH ratio were significantly reduced. Insulin sensitivity, expressed as the glucose-to-insulin ratio, was significantly improved under glucose load after 6 months of treatment. Spontaneous LH episodic release showed a significant reduction in pulse amplitude with no changes in pulse frequency. Menstrual cyclicity was restored in all amenorrheic and oligomenorrheic women. The ovarian volume and Ferriman-Gallwey scores also were significantly reduced.

Conclusion(s): Metformin administration improves reproductive axis functioning in hyperandrogenic nonobese PCOS patients. By acting on the ovary and restoring normal ovarian activity, metformin positively modulates the reproductive axis (namely GnRH-LH episodic release).