Medroxyprogesterone-induced endocrine alterations after menopause.
OBJECTIVE: To evaluate endocrine responses to short-term medroxyprogesterone acetate (MPA) administered as a respiratory stimulant in postmenopausal women with mild nocturnal hypoxemia. DESIGN: Open-label trial with 14-day MPA (60 mg daily) and 3-week follow-up posttreatment. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, and insulin-like growth factor-I (IGF-I) were assessed at baseline, while on MPA and at the 3-week washout in eight subjects. RESULTS: With MPA, FSH decreased by 47.5% (p < 0.01) and LH by 64.9% (p < 0.001), whereas IGF-I increased by 39.6% (p < 0.01). FSH and LH remained suppressed at the 3-week washout (-23.8%, p < 0.05 and -44.3%, p < 0.01, respectively). IGF-I returned to pretreatment level at the 3-week washout. Neither serum estradiol nor progesterone concentrations changed during or after progestogen therapy. CONCLUSIONS: Daily administration of MPA (60 mg) for 2 weeks has both immediate (FSH, LH and IGF-I) and sustained (FSH, LH) effects up to 3 weeks after treatment. Therefore, prolonged MPA-induced effects should be taken into account when interpreting hormone assessments after progestogen therapy.