Effects of growth hormone and insulin-like growth factor-i on
glucocorticoid-induced protein catabolism in man.
Oehri, Martin, Ronald Ninnis, Jr.g Girard, Felix J. Frey, and Ulrich
Keller.
DEPARTMENTS OF RESEARCH AND OF INTERNAL MEDICINE, UNIVERSITY
HOSPITAL BASEL; ENDOCRINOLOGICAL PRACTICE, BASEL AND DIVISION OF
NEPHROLOGY, DEPARTMENT OF MEDICINE, UNIVERSITY HOSPITAL BERN, BERN,
SWITZERLAND
APStracts 2:0241E, 1995.
The effects of similar increases in total IGF-I plasma concentrations
achieved by either rh-GH or rh-IGF-I administration on whole body
protein and glucose kinetics were assessed. 26 healthy subjects
received methylprednisolone (0.5 mg/kg/d orally) during 6 days in
combination with either placebo (saline s.c.), GH (0.3 mg/kg/d s.c.),
or IGF-I (80 g/kg/d s.c.) in a double blind randomized fashion.
Glucocorticoid administration resulted in protein catabolism as
indicated by an increase in leucine flux and a 62 13% increase in
leucine oxidation (1-13C-leucine infusion technique); this increase
was abolished by GH (-1 18%) and statistically insignificant during
IGF-I treatment (+53 25%). GH increased endogenous glucose production
by 28 8 %, augmented glucocorticoid-induced insulin resistance of
peripheral glucose clearance (euglycemic clamp) and increased
circulating lipids. IGF-I administration resulted in both, increased
endogenous glucose production and increased peripheral glucose
clearance such that plasma glucose concentrations remained unchanged.
Glucocorticoid-induced insulin resistance of glucose clearance was
unchanged by IGF-I. IGF-I lowered circulating GH and insulin and
altered IGF binding proteins which all may have reduced bioactivity
of IGF-I. The data demonstrate that in spite of similar total IGF-I
plasma concentrations during treatment, GH and IGF-I exert markedly
different effects on whole body leucine, glucose and lipid
metabolism.
Received 26 July 1995; accepted in final form 10 November 1995.
APS Manuscript Number E351-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 8 December 95