Dynamic changes of growth hormone-binding protein concentrations in normal men and patients with acromegaly: effects of short-term fasting.

Abstract

Plasma concentrations of growth hormone (GH) and GH-binding protein (GHBP) were measured at hourly intervals in five healthy men and five patients with acromegaly during the fed state and after a 5-day fast. GHBP concentrations (both total and complexed with endogenous GH) were analyzed by the ligand-mediated immunofunctional assay (LIFA). Total GHBP was similar in both groups during the fed state (104.4 +/- 5.2 and 101.6 +/- 10.3 pmol/L), did not exhibit a diurnal rhythm, and was unchanged by fasting (91.9 +/- 5.4 and 109.9 +/- 10.5 pmol/L, respectively). However, the GHBP/GH complex concentration was significantly higher in acromegalics than in controls (41.0 +/- 2.8 v 18.0 +/- 2.2 pmol/L, respectively; P < .05), closely followed diurnal GH rhythm in normals, and was significantly correlated with mean 24-hour GH concentrations (r = .86, P < .01). We conclude that plasma concentrations of GHBP are stable throughout the day and are unchanged either by short-term calorie deprivation or by chronic exposure to high levels of endogenous GH. In contrast, GHBP/GH complex concentrations are altered both acutely and chronically by ambient GH.

• Authors: P J Ho, N Gesundheit, W L Wong, S H Huang, R D Friberg, A L Barkan
• Journal: Metabolism: clinical and experimental (Metabolism) Vol. 44 Issue 5 Pg. 667-72 (May 1995) ISSN: 0026-0495 [Print] United States
• PMID: 7752917 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Carrier Proteins
• Growth Hormone
• somatotropin-binding protein

Topics

• Acromegaly (blood)
• Adult
• Aged
• Analysis of Variance
• Carrier Proteins (blood)
• Cohort Studies
• Eating
• Fasting
• Female
• Growth Hormone (blood)
• Humans
• Male
• Middle Aged
• Reference Values