Regulated recovery of pulsatile growth hormone secretion from negative feedback: A preclinical investigation

Johannes D. Veldhuis, Cyril Y. Bowers

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Although stimulatory (feedforward) and inhibitory (feedback) dynamics jointly control neurohormone secretion, the factors that supervise feedback restraint are poorly understood. To parse the regulation of growth hormone (GH) escape from negative feedback, 25 healthy men and women were studied eight times each during an experimental GH feedback clamp. The clamp comprised combined bolus infusion of GH or saline and continuous stimulation by saline GH-releasing hormone (GHRH), GHRP-2, or both peptides after randomly ordered supplementation with placebo (both sexes) vs. E2 (estrogen; women) and T (testosterone; men). Endpoints were GH pulsatility and entropy (a model-free measure of feedback quenching). Gender determined recovery of pulsatile GH secretion from negative feedback in all four secretagog regimens (0.003 ≤ P≤0.017 for women>men). Peptidyl secretagog controlled the mass, number, and duration of feedbackinhibited GH secretory bursts (each, P < 0.001). E 2/T administration potentiated both pulsatile (P=0.006) and entropic (P=0.001) modes of GH recovery. IGF-I positively predicted the escape of GH secretory burst number and mode (P=0.022), whereas body mass index negatively forecast GH secretory burst number and mass (P =0.005). The composite of gender, body mass index, E 2, IGF-I, and peptidyl secretagog strongly regulates the escape of pulsatile and entropic GH secretion from autonegative feedback. The ensemble factors identified in this preclinical investigation enlarge the dynamic model of GH control in humans.

Original languageEnglish (US)
Pages (from-to)R1143-R1152
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume301
Issue number4
DOIs
StatePublished - Oct 2011

Keywords

  • GHRH
  • Ghrelin
  • Human
  • Pulsatility
  • Sex steroid
  • Somatotropin
  • Testosterone

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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