In vivo metabolic action of insulin-like growth factor I in adult rats.
The acute metabolic actions of insulin-like growth factor I were studied in anaesthetized adult rats and its potency was compared to that of insulin. Following an i.v. bolus injection of insulin-like growth factor I a dose-dependent decrease of blood glucose and serum non-esterified fatty acid concentrations was noted with a potency of about 2% that of insulin. Stimulation of total body glucose disposal during euglycaemic clamping required approximately 50 times higher insulin-like growth factor I serum concentrations to achieve an identical half-maximal response. A similar difference in potency was observed for the stimulatory action on 2-deoxyglucose uptake and on glycogen formation in skeletal muscle. Lipogenesis in epididymal fat pads was increased dose-dependently by both hormones requiring approximately 30 times higher half-maximally effective serum concentrations of insulin-like growth factor I. These data demonstrate that insulin-like growth factor I exerted acute insulin-like metabolic actions in vivo with low potency. These effects were probably mediated via insulin receptors. A preferential stimulation of glucose metabolism in skeletal muscle was not observed.
Schmitz
F
F
Department of Medicine, University of Göttingen, FRG.
Hartmann
H
H
Stümpel
F
F
Creutzfeldt
W
W
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006003:Glycogen / Q000096:biosynthesis; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007700:Kinetics; D008066:Lipolysis / Q000187:drug effects*; D008112:Liver Glycogen / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008112:Liver Glycogen; D007334:Insulin-Like Growth Factor I; D006003:Glycogen; D005947:Glucose