title: Short-term modulation of gonadotropin secretion by progesterone during the luteal phase.
abstract: Progesterone (P) levels were acutely augmented by intravenous (IV) infusion in seven women in the midluteal phase to ascertain if short-term changes in P levels have an effect on gonadotropin secretion. During four 6-hour intervals of alternating control and IV P infusion, each subject underwent blood sampling for luteinizing hormone (LH), follicle-stimulating hormone (FSH), and P every 20 minutes for 24 hours. As a result of the P infusions, mean (+/- SE) P levels rose 72% from a control level of 26.24 +/- 2.13 to 45.22 +/- 3.47 nmol/L, whereas mean LH levels were reduced by 20% from a control level of 4.82 +/- 0.67 to 3.85 +/- 0.66 IU/L. During P infusions, mean LH pulse amplitude was reduced by 33% from 3.33 +/- 0.37 to 2.23 +/- 0.28 IU/L. The mean LH interpulse interval increased by 93% (2.56 +/- 0.14 to 4.92 +/- 0.15/h) when the interval between pulses was interdicted by the onset of P infusion. The infusion of P reduced mean FSH levels by 10% from 3.34 +/- 0.41 to 3.01 +/- 0.35 IU/L. These findings suggest that acute elevations in P levels within the physiological range have a short-term inhibitory effect on gonadotropin secretion during the midluteal phase.
authors.affiliation: Department of Obstetrics and Gynecology, University of Vermont College of Medicine, Burlington 05405.
authors.forename: M
authors.initials: M
authors.lastname: Gibson
authors.forename: S T
authors.initials: ST
authors.lastname: Nakajima
authors.forename: T L
authors.initials: TL
authors.lastname: McAuliffe
mesh_terms: D000328:Adult; D005246:Feedback; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006062:Gonadotropins / Q000378:metabolism*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D007262:Infusions, Intravenous; D008183:Luteal Phase / Q000187:drug effects*; D007986:Luteinizing Hormone / Q000097:blood; D011374:Progesterone / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D006062:Gonadotropins; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone