title: Beta-endorphin levels in the human menstrual cycle.
abstract: To examine the fluctuation in plasma beta-Endorphin (beta-EP) concentration throughout the menstrual cycle, 8 healthy females with normal cycles were studied. After an overnight fast, the subject's blood samples were drawn between 8 and 10 a.m. They gave blood at 2 or 4 day intervals through three menstrual cycles. Using the LH surge as day 0, the mean beta-EP concentrations were higher on days -10, -9, -8 (6.5 +/- 2.6, 6.9 +/- 3.8 and 6.7 +/- 2.7 pmol/l, follicular phase), on days -1, 0, +1 (9.2 +/- 3.3, 9.1 +/- 5.2 and 8.8 +/- 3.3 pmol/l, periovulatory phase), and on days +9 and +12 (8.6 +/- 2.5 and 8.8 +/- 3.8 pmol/l, luteal phase). Most beta-EP levels were low during menstruation. The rise and fall in beta-EP and its relation to temporal LH and FSH secretion are discussed. The findings show that three beta-EP rises take place during the menstrual cycle and that beta-EP may be involved in the regulation of ovulation.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston.
authors.forename: C J
authors.initials: CJ
authors.lastname: Chuong
authors.forename: E R
authors.initials: ER
authors.lastname: Smith
authors.forename: Y
authors.initials: Y
authors.lastname: Tsong
mesh_terms: D000328:Adult; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D008597:Menstrual Cycle / Q000097:blood*; D011863:Radioimmunoassay; D001615:beta-Endorphin / Q000097:blood*
chemical_list: D001615:beta-Endorphin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone