title: Progesterone has rapid positive feedback actions on LH release but fails to reduce LH pulse frequency within 12 h in estradiol-pretreated women.
abstract: In women, progesterone suppresses luteinizing hormone (LH) (gonadotropin-releasing hormone) pulse frequency, but how rapidly this occurs is unknown. In estradiol-pretreated women in the late follicular phase, progesterone administration at 1800 did not slow sleep-associated LH pulse frequency. However, mechanisms controlling LH pulse frequency may differ according to sleep status; and we thus hypothesized that progesterone acutely suppresses waking LH pulse frequency. This was a randomized, double-blind, crossover study of LH secretory responses to progesterone versus placebo administered at 0600. We studied 12 normal women in the late follicular phase (cycle days 7-11), pretreated with 3 days of transdermal estradiol (0.2 mg/day). Subjects underwent a 24-h blood sampling protocol (starting at 2000) and received either 100 mg oral micronized progesterone or placebo at 0600. In a subsequent menstrual cycle, subjects underwent an identical protocol except that oral progesterone was exchanged for placebo or vice versa. Changes in 10-h LH pulse frequency were similar between progesterone and placebo. However, mean LH, LH pulse amplitude, and mean follicle-stimulating hormone exhibited significantly greater increases with progesterone. Compared to our previous study (progesterone administered at 1800), progesterone administration at 0600 was associated with a similar increase in mean LH, but a less pronounced increase in LH pulse amplitude. We conclude that, in estradiol-pretreated women in the late follicular phase, a single dose of progesterone does not suppress waking LH pulse frequency within 12 h, but it acutely amplifies mean LH and LH pulse amplitude - an effect that may be influenced by sleep status and/or time of day.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: Eleanor G
authors.initials: EG
authors.lastname: Hutchens
authors.affiliation: University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Ramsey
authors.affiliation: College and Graduate School of Arts and Sciences, University of Virginia, Charlottesville, Virginia.
authors.forename: Louisa C
authors.initials: LC
authors.lastname: Howard
authors.affiliation: Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: Michelle Y
authors.initials: MY
authors.lastname: Abshire
authors.affiliation: Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: James T
authors.initials: JT
authors.lastname: Patrie
authors.affiliation: Division of Endocrinology and Metabolism, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia Center for Research in Reproduction, University of Virginia School of Medicine, Charlottesville, Virginia cm2hq@virginia.edu.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: McCartney
mesh_terms: D000279:Administration, Cutaneous; D000293:Adolescent; D002940:Circadian Rhythm / Q000502:physiology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004958:Estradiol / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000494:pharmacology*; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005498:Follicular Phase / Q000187:drug effects; D007987:Gonadotropin-Releasing Hormone / Q000097:blood / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D011673:Pulsatile Flow / Q000187:drug effects / Q000502:physiology*; D055815:Young Adult
chemical_list: D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: Circadian rhythm; estradiol; gonadotropin surge; gonadotropin‐releasing hormone; luteinizing hormone; luteinizing hormone surge; progesterone