Objective: To demonstrate that hypoestrogenism in menopause is in part responsible for the decrease in circulating dehydroepiandrosterone sulfate (DHEA-S) and ACTH levels. To test this hypothesis, 25 postmenopausal women aged 47-60 years, were given orally conjugated equine estrogen (CEE) to study the effect on circulating DHEA-S, cortisol and ACTH. Design: A prospective, non-blinded study was performed. Hormonal levels were analyzed before and after three cycles of CEE 0.625 mg/day for 21 days followed each by chlormadinone acetate for 5 days. Results: Low baseline levels of DHEA-S increased significantly after HRT (1.71+/-0.75 to 3.3+/-1.5 micromol/l, (P