title: Acute effects of insulin-like growth factor I on inter-organ amino acid flux in protein-catabolic dogs.
abstract: The effects of acute administration of human recombinant insulin-like growth factor-I (rhIGF-I) on amino acid (AA) flux between hindlimbs, liver and gut were investigated in anaesthetized post-operative dogs. rhIGF-I produced about a 10-fold increase in plasma IGF-I concentrations above baseline values (P < 0.001), increased the plasma levels of glucagon and adrenaline (P < 0.05), and evoked a fall in plasma glucose (-55 +/- 8%; (P < 0.001) and plasma total AA levels (-23 +/- 8%; P < 0.05). AA flux in post-absorptive dogs under NaCl infusions was characterized by an efflux of AA from the hindlimbs (as a result of the protein-catabolic situation), an equal AA balance across the gut and an AA uptake by the liver. The administration of rhIGF-I increased hepatic AA uptake in the NaCl group from 3.51 +/- 0.8 to 7.5 +/- 0.4 mumol/min per kg (P < 0.01) and in the AA-infused group from 16.8 +/- 0.6 to 22.4 +/- 1.5 mumol/min per kg (P < 0.05), but did not influence the AA balance across hindlimbs and gut. Glucose infusions normalized the plasma concentrations of counter-regulatory hormones without influencing the inter-organ AA balances. We conclude that hypoaminoacidaemia caused by rhIGF-I infusions is the result of a stimulated AA uptake by the liver, but is unrelated to alterations of AA exchange across the hindlimbs.
authors.affiliation: Institute of Biochemical Pharmacology, University of Vienna, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Roth
authors.forename: L
authors.initials: L
authors.lastname: Valentini
authors.forename: T
authors.initials: T
authors.lastname: Hölzenbein
authors.forename: S
authors.initials: S
authors.lastname: Winkler
authors.forename: T
authors.initials: T
authors.lastname: Sautner
authors.forename: H
authors.initials: H
authors.lastname: Hörtnagl
authors.forename: J
authors.initials: J
authors.lastname: Karner
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004285:Dogs; D004837:Epinephrine / Q000097:blood; D005934:Glucagon / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism; D009638:Norepinephrine / Q000097:blood; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D007328:Insulin; D011506:Proteins; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D005934:Glucagon; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine