help button home button Endocrine Society JCEM
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
This version published online on October 26, 2009
Journal of Clinical Endocrinology & Metabolism , doi:10.1210/jc.2009-1769
This Article
Right arrow Author Manuscript (PDF)
Right arrow Supplemental Data
Right arrow Submit a related Letter to the Editor
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Google Scholar
Right arrow Articles by Hudson, S. B.
Right arrow Articles by Veldhuis, J. D.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hudson, S. B.
Right arrow Articles by Veldhuis, J. D.

Submitted on August 18, 2009
Accepted on October 8, 2009

Pre- Versus Postmenopausal Age, Estradiol, and Peptide-Secretagogue Type Determine Pulsatile Growth Hormone Secretion in Healthy Women: Studies Using Submaximal Agonist Drive and an Estrogen Clamp

Susan B. Hudson, Darrell R. Schroeder, Joy N. Bailey, Kristi L. Mielke, Dana Erickson, John M. Miles, Cyril Y. Bowers, and Johannes D. Veldhuis*

Department of Obstetrics and Gynecology (S.B.H.), Biomedical Statistics and Informatics (D.R.S.), Endocrine Research Unit (J.N.B., K.L.M., D.E., J.M.M., J.D.V.), Mayo School of Graduate Medical Education, Clinical Translational Research Center, Mayo Clinic, Rochester, Minnesota 55905; and Endocrine Division (C.Y.B.), Department of Medicine, Tulane University Health Science Center, New Orleans, Louisiana 70112

* To whom correspondence should be addressed. E-mail: veldhuis.johannes{at}mayo.edu.

Context: GH-releasing peptide (GHRP), GHRH, and somatostatin are physiological regulators of pulsatile GH secretion.

Hypothesis: Age, independently of abdominal visceral fat (AVF) and basal (nonpulsatile) GH secretion, damps pulsatile GH secretion driven by physiological (rather than pharmacological) amounts of GHRP and GHRH in an experimentally controlled estradiol (E2) milieu.

Design and Setting: A prospectively randomized, double-blind parallel-cohort study was conducted at an academic medical center.

Participants: Community-dwelling healthy premenopausal (PRE, age 24 ± 0.8 yr, n = 20) and postmenopausal (POST, age 63 ± 1.8 yr, n = 22) women participated in the study.

Interventions: Gonadal-axis down-regulation with leuprolide was followed by randomized addback of placebo or transdermal E2 and separate-day iv bolus injections of a half-maximally stimulatory dose of GHRP-2 or GHRH (each 0.33 μg/kg).

Analysis: Three-way analysis of covariance included main factors age, E2 status, and secretagogue type and covariates AVF and basal GH secretion.

Results: Submaximally stimulated pulsatile GH secretion was positively determined by PRE vs. POST age (P < 0.001), E2 repletion vs. depletion (P = 0.001) and GHRP-2 vs. GHRH stimulation (P < 0.001), after adjustment for AVF and basal secretion. E2 vs. placebo elevated fasting mean GH concentrations in both PRE and POST women (P = 0.006) but increased basal (nonpulsatile) GH secretion in PRE only (P = 0.002). PRE vs. POST age prolonged GHRH-driven GH secretory bursts by 36% (P = 0.006).

Conclusion: PRE vs. POST age, E2 availability, and physiological peptide drive are triple determinants of pulsatile GH secretion independently of abdominal visceral fat and nonpulsatile GH secretion in healthy women.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals
Copyright © 2009 by The Endocrine Society