scholarly journals Gonadal Status and Body Mass Index Jointly Determine Growth Hormone (GH)-Releasing Hormone/GH-Releasing Peptide Synergy in Healthy Men

2008 ◽  
Vol 93 (3) ◽  
pp. 944-950 ◽  
Author(s):  
Remberto C. Paulo ◽  
Mihaela Cosma ◽  
Cacia Soares-Welch ◽  
Joy N. Bailey ◽  
Kristi L. Mielke ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Growth Hormone ◽  
Body Mass ◽  
Healthy Men ◽  
Releasing Hormone ◽  
Gonadal Status

scholarly journals Differential pulsatile secretagogue control of GH secretion in healthy men

2013 ◽  
Vol 304 (9) ◽  
pp. R712-R719 ◽  
Author(s):  
Catalina Norman ◽  
John Miles ◽  
Cyril Y. Bowers ◽  
Johannes D. Veldhuis
Keyword(s):  
Body Mass Index ◽  
Growth Hormone ◽  
Regression Analysis ◽  
Body Mass ◽  
Older Men ◽  
Regulatory Mechanisms ◽  
Double Blind ◽  
Healthy Men ◽  
Gh Secretion ◽  
Integrated Regulation

Pulsatile growth hormone (GH) secretion putatively reflects integrated regulation by GH-releasing hormone (GHRH), somatostatin (SST), and GH-releasing peptide (GHRP). GHRH and SST secretion is itself pulsatile. However, how GHRH and SST pulses act along with GHRP to jointly determine pulsatile GH secretion is unclear. Moreover, how testosterone (T) modulates such interactions is unknown. These queries were assessed in a prospectively randomized, placebo-controlled double-blind cohort comprising 26 healthy older men randomized to testosterone (T) vs. placebo supplementation. Pulses of GHRH, SST, or saline were infused intravenously at 90-min intervals for 13 h, along with either continuous saline or ghrelin analog (GHRP-2). The train of pulses was followed by a triple stimulus (combined l-arginine, GHRH, and GHRP-2) to estimate near-maximal GH secretion over a final 3 h. Testosterone vs. placebo supplementation doubled pulsatile GH secretion during GHRH pulses combined with continuous saline (GHRH/saline) ( P < 0.01). Pulsatile GH secretion correlated positively with T concentrations (270–1,170 ng/dl) in the 26 men during saline pulses/saline ( P = 0.015, R2 = 0.24), GHRH pulses/saline ( P = 0.020, R2 = 0.22), and combined GHRH pulses/GHRP-2 ( P = 0.016, R2 = 0.25) infusions. Basal nonpulsatile GH secretion correlated with T during saline pulses/GHRP-2 drive ( P = 0.020, R2 = 0.16). By regression analysis, pulsatile GH secretion varied negatively with body mass index (BMI) during saline/GHRP-2 infusion ( P = 0.001, R2 = 0.36), as well as after the triple stimulus preceded by GHRH/GHRP-2 ( P = 0.013, R2 = 0.23). Mean (10-h) GH concentrations under GHRP-2 were predicted jointly by estradiol (positively) and BMI (negatively) ( P < 0.001, R2 = 0.520). These data indicate that estradiol, T, and BMI control pulsatile secretagogue-specific GH-regulatory mechanisms in older men.

Effect of body mass index and fat distribution on insulin sensitivity, secretion, and clearance in nonobese healthy men.

1992 ◽  
Vol 75 (1) ◽  
pp. 170-175 ◽  
Author(s):  
C Walton ◽  
I F Godsland ◽  
A J Proudler ◽  
C V Felton ◽  
V Wynn
Keyword(s):  
Body Mass Index ◽  
Insulin Sensitivity ◽  
Body Mass ◽  
Fat Distribution ◽  
Healthy Men
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