Human GH pulsatility: an ensemble property regulated by age and gender

J Endocrinol Invest. 2003 Sep;26(9):799-813. doi: 10.1007/BF03345229.

Abstract

Age and gender impact the full repertoire of neurohormone systems, including most prominently the somatotropic, gonadotropic and lactotropic axes. For example, daily GH production is approximately 2-fold higher in young women than men and varies by 20-fold by sexual developmental status and age. Deconvolution estimates of 24-h GH secretion rates exceed 1200 microg/m2 in adolescents and fall below 60 microg/m2 in aged individuals. The present overview highlights plausible factors driving such lifetime variations in GH availability, i.e., estrogen, aromatizable androgen, hypothalamic peptides and negative feedback by GH and IGF-I. In view of the daunting complexity of potential neuromodulatory signals, we underline the utility of conceptualizing a simplified three-peptide regulatory ensemble of GHRH, GHRP (ghrelin) and somatostatin. The foregoing signals act as individual and conjoint mediators of adaptive GH control. Regulation is enforced at 3-fold complementary time scales, which embrace pulsatile (burst-like), entropic (orderly) and 24-h rhythmic (nycthemeral) modes of GH release. This unifying platform offers a convergent perspective of multivalent control of GH outflow.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Androgens / pharmacology
  • Child
  • Circadian Rhythm
  • Estrogens / pharmacology
  • Feedback, Physiological
  • Female
  • Human Growth Hormone / metabolism*
  • Humans
  • Hypothalamo-Hypophyseal System / physiology*
  • Male
  • Middle Aged
  • Sex Factors

Substances

  • Androgens
  • Estrogens
  • Human Growth Hormone