Effects of insulin-like growth factor I combined with growth hormone on glucocorticoid-induced whole-body protein catabolism in man.
Treatment with insulin-like growth factor I (IGF-I) alone failed to affect glucocorticoid-induced protein catabolism in a previous study from our laboratory. To assess the effects of the combination of IGF-I and GH in a similar protocol, 24 normal subjects received (in a double-blind, randomized, placebo-controlled manner) s.c. injections of either GH alone (0.3 IU/kg.day), the combination of IGF-I (80 micrograms/kg.day) and GH (0.3 IU/kg.day), or placebo for a period of 6 days during which they were treated with methylprednisolone (0.5 mg/kg.day). Whole-body protein kinetics measured, using the [1-13C]-leucine infusion technique, demonstrated that leucine flux (a parameter of protein breakdown) increased during administration of glucocorticoids alone (placebo group) and during GH-treatment, whereas the glucocorticoid-induced increase was abolished during IGF-I plus GH (P < 0.03 vs. GH). Leucine oxidation (a parameter of irreversible protein catabolism) increased in the placebo group (+60 +/- 14.5%, P < 0.005, day 7 vs. day 1), remained unchanged in the GH group (+2.5 +/- 10%), and decreased in the combination group (-17.7 +/- 3.3%, P < 0.002, day 7 vs. day 1). Glucose MCR decreased in the group receiving placebo (P < 0.05) and remained unchanged during combined treatment with IGF-I plus GH. It is concluded that glucocorticoid-induced protein, catabolism (leucine oxidation) is abolished during coadministration of GH (anticatabolic effect), whereas treatment with IGF-I and GH results in a net anabolic effect without adverse effects on peripheral glucose clearance.
Berneis
K
K
Department of Research, University Hospital Basel, Switzerland.
Ninnis
R
R
Girard
J
J
Frey
B M
BM
Keller
U
U
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D004311:Double-Blind Method; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000097:blood; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008297:Male; D008775:Methylprednisolone / Q000097:blood / Q000494:pharmacology*; D010919:Placebos; D011506:Proteins / Q000378:metabolism*
D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D010919:Placebos; D011506:Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D005934:Glucagon; D007930:Leucine; D008775:Methylprednisolone