Growth hormone regulation by growth hormone-releasing hormone in infant rhesus monkeys.
Wheeler. M D MD; Wehrenberg. W W WW; Styne. D M DM
Key Findings
- Giving an antibody that neutralizes GHRH lowered serum GH at 1‑2 and 7‑9 days old, but not at 28‑31 days.
- A GHRH antagonist reduced GH only at 1‑2 days old, with no effect at 7 or 14 days.
- Endogenous GHRH drives basal GH secretion strongly in the first 1‑2 days of life, but its role diminishes as the infant ages.
Practical Outcomes
- For adult biohackers, this study offers little direct guidance. It suggests that GHRH‑based peptides may have limited impact on GH levels once the early neonatal period is passed, so timing and age are critical factors when considering GHRH analogs for growth‑hormone modulation.
Summary
In baby rhesus monkeys, the body’s own growth‑hormone‑releasing hormone (GHRH) is important for making growth hormone (GH) right after birth, but its influence drops off after the first week. Blocking GHRH with an antibody or a short‑acting antagonist lowered GH levels in the first few days, but not later.
Abstract
To study the relationship of endogenous GHRH to the changes seen in serum GH concentration in neonatal primates, we administered antiserum to GHRH (GHRH-Ab) or GHRH antagonist, (N-Acetyl-Tyr1,D-Arg2)GHRH-(1-29)-NH2, to unanesthetized, fasted rhesus monkeys, 1-31 days of age, via an acutely placed venous catheter. The administration of GHRH-Ab resulted in a significant decrease in serum GH concentration at 1-2 and 7-9 days, but not at 28-31 days of age. The administration of GHRH antagonist resulted in a significant decrease in serum GH concentrations at 1-2 days, but not at 7 or 14 days of age. These results imply that basal serum GH is more dependent on endogenous GHRH at 1-2 days than after 7-28 days of age. This suggests developmental changes in the hypothalamic regulation of GH secretion with advancing age in the neonatal period.
Study Information
pubmed
1991
10.1159/000243384
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