A comparison of the effects of insulin-like growth factor-I, insulin and combined infusions of insulin and insulin-like growth factor-I on glucose metabolism in dogs.
The effect of infusions of recombinant insulin-like growth factor-I (IGF-I) (34, 103 or 688 pmol kg-1 min-1), insulin (3.4, 10.3 or 68.8 pmol kg-1 min-1) or combined infusions (34 pmol IGF-I + 3.4 pmol kg-1 min-1 insulin or 103 pmol IGF-I + 3.4 pmol kg-1 min-1 insulin) on glucose metabolism was investigated in dogs using a [3-3H]-glucose infusion and euglycaemic clamp. All insulin doses decreased glucose production rate (Ra) in a dose-dependent manner (P < 0.05). All IGF-I doses decreased glucose Ra (P < 0.05) but this decrease was not dose dependent. The decrease in glucose Ra with the combined infusion of 34 pmol kg-1 min-1 IGF-I + 3.4 pmol kg-1 min-1 insulin was greater than 34 pmol kg-1 min-1 IGF-I (P < 0.05) but not different from 3-4 pmol kg-1 min-1 insulin. All insulin and IGF-I doses increased glucose utilization rate (Rd) in a dose-dependent manner (P < 0.01). The increase in glucose utilization was greater following both combined infusions than with either component infused alone (P < 0.05). Although at the doses selected, insulin and IGF-I had similar effects on glucose utilization with additive effects when the two peptides were combined, IGF-I was less effective than insulin in suppressing glucose production.
Shojaee-Moradie
F
F
Department of Medicine, UMDS, London, UK.
Umpleby
A M
AM
Thomason
M J
MJ
Jackson
N C
NC
Boroujerdi
M A
MA
Sönksen
P H
PH
Skottner
A
A
Jones
R H
RH
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008657:Metabolic Clearance Rate; D011994:Recombinant Proteins / Q000494:pharmacology
D001786:Blood Glucose; D007328:Insulin; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D005947:Glucose