Progesterone and medroxyprogesterone acetate effects on central and peripheral allopregnanolone and beta-endorphin levels.

The increased use of hormonal therapies has led to the study of the properties of different progestin molecules and their effects on the central nervous system. The central and peripheral levels of neurosteroid allopregnanolone and the opioid peptide beta-endorphin (beta-END) are regulated by estrogens. The aim of the present study was to investigate the effects of a 2-week oral treatment with micronized progesterone or medroxyprogesterone acetate (MPA) alone or in addition to estradiol valerate (E2V) on central and peripheral allopregnanolone and beta-END levels in ovariectomized (OVX) female rats.

Conjugated equine estrogens reverse the effects of aging on central and peripheral allopregnanolone and beta-endorphin levels in female rats.

Objective: To compare beta-endorphin and allopregnanolone levels and their response to a 2-week oral estrogen treatment with conjugated equine estrogens (CEE) in young ovariectomized (ovx) and in healthy aged female rats.

Design: Prospective study.

Setting: Animal laboratory in an academic environment.

Conjugated equine estrogens, estrone sulphate and estradiol valerate oral administration in ovariectomized rats: effects on central and peripheral allopregnanolone and beta-endorphin.

Objectives: Several natural or synthetic estrogenic molecules are commonly used in oral hormone replacement therapy for the relief of menopausal complaints and for the primary prevention of cardiovascular disease and osteoporosis. Little information is available concerning the comparative efficacy of different compounds on neuroendocrine function. The opioid peptide beta-endorphin (beta-EP), and the neurosteroid allopregnanolone are considered markers of neuroendocrine function and their synthesis and action is regulated by gonadal steroids.