TY - JOUR
T1 - Estradiol regulates GH-releasing peptide's interactions with GH-releasing hormone and somatostatin in postmenopausal women
AU - Norman, Catalina
AU - Rollene, Nanette L.
AU - Erickson, Dana
AU - MMiles, John
AU - Bowers, Cyril Y.
AU - Veldhuis, Johannes D.
PY - 2014/1
Y1 - 2014/1
N2 - Objective: Estrogen stimulates pulsatile secretion of GH, via mechanisms that are largely unknown. An untested hypothesis is that estradiol (E 2) drives GH secretion by amplifying interactions among GH-releasing hormone (GHRH), somatostatin (SS), and GH-releasing peptide (GHRP). Design: The design comprised double-blind randomized prospective administration of transdermal E2 vs placebo to healthy postmenopausal women (n=24) followed by pulsatile GHRH or SS infusions for 13 h overnight with or without continuous GHRP2 stimulation. Methods: End points were mean concentrations, deconvolved secretion, and approximate entropy (ApEn; a regularity measure) of GH. Results: By generalized ANOVA models, it was observed that E2 vs placebo supplementation: i) augmented mean (13-h) GH concentrations (P=0.023), GHRH-induced pulsatile GH secretion over the first 3 h (P=0.0085) and pulsatile GH secretion over the next 10 h (P=0.054); ii) increased GHRP-modulated (P=0.022) and SS-modulated (P<0.001) GH ApEn; and iii) did not amplify GHRH/GHRP synergy during pulsatile GH secretion. By linear regression, E 2 concentrations were found to be positively correlated with GH secretion during GHRP2 infusion (P=0.022), whereas BMI was found to be negatively correlated with GH secretion during GHRH (P=0.006) and combined GHRH/GHRP (P=0.015) stimulation. E2 and BMI jointly determined triple (combined L-arginine, GHRH, and GHRP2) stimulation of GH secretion after saline (R2=0.44 and P=0.003) and pulsatile GHRH (R2=0.39 and P=0.013) infusions. Conclusion: In summary, in postmenopausal women, E 2 supplementation augments the amount (mass) and alters the pattern (regularity) of GH secretion via interactions among GHRH, SS, GHRP, and BMI. These outcomes introduce a more complex model of E2 supplementation in coordinating GH secretion in aging women.
AB - Objective: Estrogen stimulates pulsatile secretion of GH, via mechanisms that are largely unknown. An untested hypothesis is that estradiol (E 2) drives GH secretion by amplifying interactions among GH-releasing hormone (GHRH), somatostatin (SS), and GH-releasing peptide (GHRP). Design: The design comprised double-blind randomized prospective administration of transdermal E2 vs placebo to healthy postmenopausal women (n=24) followed by pulsatile GHRH or SS infusions for 13 h overnight with or without continuous GHRP2 stimulation. Methods: End points were mean concentrations, deconvolved secretion, and approximate entropy (ApEn; a regularity measure) of GH. Results: By generalized ANOVA models, it was observed that E2 vs placebo supplementation: i) augmented mean (13-h) GH concentrations (P=0.023), GHRH-induced pulsatile GH secretion over the first 3 h (P=0.0085) and pulsatile GH secretion over the next 10 h (P=0.054); ii) increased GHRP-modulated (P=0.022) and SS-modulated (P<0.001) GH ApEn; and iii) did not amplify GHRH/GHRP synergy during pulsatile GH secretion. By linear regression, E 2 concentrations were found to be positively correlated with GH secretion during GHRP2 infusion (P=0.022), whereas BMI was found to be negatively correlated with GH secretion during GHRH (P=0.006) and combined GHRH/GHRP (P=0.015) stimulation. E2 and BMI jointly determined triple (combined L-arginine, GHRH, and GHRP2) stimulation of GH secretion after saline (R2=0.44 and P=0.003) and pulsatile GHRH (R2=0.39 and P=0.013) infusions. Conclusion: In summary, in postmenopausal women, E 2 supplementation augments the amount (mass) and alters the pattern (regularity) of GH secretion via interactions among GHRH, SS, GHRP, and BMI. These outcomes introduce a more complex model of E2 supplementation in coordinating GH secretion in aging women.
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U2 - 10.1530/EJE-13-0733
DO - 10.1530/EJE-13-0733
M3 - Article
C2 - 24114435
AN - SCOPUS:84890512537
SN - 0804-4643
VL - 170
SP - 121
EP - 129
JO - European journal of endocrinology
JF - European journal of endocrinology
IS - 1
ER -