Dual secretagogue drive of burst-like growth hormone secretion in postmenopausal compared with premenopausal women studied under an experimental estradiol clamp.
We show that in an experimentally enforced estradiol-predominant milieu, postmenopausal compared with premenopausal women maintain 1) decreased fasting GH and IGF-I concentrations, 2) reduced basal and pulsatile GH secretion, and 3) attenuated GH secretion after maximal stimulation by the paired secretagogues l-arginine/GH-releasing peptide (GHRP)-2, l-arginine/GHRH, and GHRP-2/GHRH. These foregoing outcomes are selective, because menopausal status did not determine mean GH secretory-burst frequency or peptide-induced waveform shortening. Abdominal visceral fat mass predicted up to 25% of the variability in fasting and stimulated GH secretion in the combined cohorts under fixed systemic estradiol availability. Accordingly, as much as three-fourths of interindividual differences in burst-like GH secretion among healthy pre- and postmenopausal women arise from age-related mechanisms independently of short-term systemic estrogen availability and relative intraabdominal adiposity.
Erickson
Dana
D
Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905, USA.
Keenan
Daniel M
DM
Mielke
Kristi
K
Bradford
Kandace
K
Bowers
Cyril Y
CY
Miles
John M
JM
Veldhuis
Johannes D
JD
D000328:Adult; D000368:Aged; D001120:Arginine / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008875:Middle Aged; D009842:Oligopeptides / Q000494:pharmacology; D017698:Postmenopause / Q000378:metabolism*; D017697:Premenopause / Q000378:metabolism*
D009842:Oligopeptides; D019382:Human Growth Hormone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine; C091874:growth hormone-releasing peptide-2