title: The progesterone positive feedback effect in women after ovariectomy.
abstract: Various ovarian substances regulate the secretion of gonadotrophins during the menstrual cycle, but there are still several unclarified issues. The aim of this study was to investigate the positive feedback effect of progesterone during the immediate period following ovariectomy. Experiments were performed in 12 normally cycling women (aged 39-49 years). Following abdominal hysterectomy plus bilateral ovariectomy performed on cycle day 3 (day 0), the women received either estradiol via skin patches (days 0-7, n = 6, group 1) or estradiol as above plus vaginal progesterone (days 1-7, n = 6, group 2). Serum estradiol values increased similarly in the two groups. After the operation, serum progesterone levels decreased significantly in group 1, while in group 2 they remained stable becoming higher than in group 1 (p < 0.05). An LH and an FSH surge occurred in group 2 with the values after the peak returning to the pre-surge baseline. In contrast, in group 1 LH and FSH levels following an initial decrease, increased gradually until the end of the experiment. These results demonstrate that, despite a variable response to estrogens, the positive feedback effect of progesterone remained intact immediately after ovariectomy in women. It is suggested that it is the combining action of estradiol and progesterone that can ensure the expression of a positive feedback mechanism in women.
authors.affiliation: Department of Obstetrics and Gynecology, Medical School, University of Thessalia, Larissa, Greece.
authors.forename: Apostolos
authors.initials: A
authors.lastname: Zavos
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Dafopoulos
authors.forename: Christina I
authors.initials: CI
authors.lastname: Messini
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Georgoulias
authors.forename: Christina
authors.initials: C
authors.lastname: Verikouki
authors.forename: George
authors.initials: G
authors.lastname: Anifandis
authors.forename: Antonios
authors.initials: A
authors.lastname: Garas
authors.forename: Ioannis E
authors.initials: IE
authors.lastname: Messinis
mesh_terms: D000282:Administration, Intravaginal; D000328:Adult; D004958:Estradiol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D025461:Feedback, Physiological / Q000187:drug effects*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D005782:Gels; D020249:Hormone Replacement Therapy; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism; D007044:Hysterectomy / Q000009:adverse effects; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D010052:Ovariectomy / Q000009:adverse effects*; D011184:Postoperative Period; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D057968:Transdermal Patch; D015854:Up-Regulation / Q000187:drug effects; D014622:Vaginal Creams, Foams, and Jellies
chemical_list: D005782:Gels; D014622:Vaginal Creams, Foams, and Jellies; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone