The effect of insulin and glucagon on splanchnic oxygen consumption.
The purpose of these experiments was to measure the influence of insulin and glucagon on the splanchnic oxygen consumption. Two experiments were performed.


METHODS
In one experiment, the influence of hyperinsulinaemia was investigated in six healthy subjects, who were studied during a euglycaemic hyperinsulinaemic clamp. In another experiment, the influence of glucagon was investigated in seven healthy subjects, who were studied twice during a pancreatic islet clamp with either supplementation of insulin and glucagon, or of insulin alone. In both situations the measurements were performed during euglycaemia. Splanchnic oxygen consumption and net substrate balances were studied by the arterio-hepatic venous catheterisation technique and measurement of splanchnic blood flow in all experiments.


RESULTS
During the euglycaemic hyperinsulinaemic clamp, the splanchnic blood flow increased significantly and the splanchnic oxygen consumption decreased by about 20%, while the net splanchnic glucose output reversed to a net uptake. In the pancreatic islet clamp experiments there was a significant difference between the net splanchnic glucose outputs whether glucagon and insulin or only insulin was supplemented. In spite of this, the splanchnic oxygen consumption decreased by about 20% in both situations, i.e. independent of glucagon supplementation. In both experiments there was a pronounced inhibition of lipolysis, which led to decreased fatty acids availability to the liver. This resulted in a concomitant decrease in hepatic ketone body formation. This decrease could account for about 30% of the decrease in splanchnic oxygen consumption.


CONCLUSIONS
The reduction in splanchnic oxygen consumption can be explained by decreased ketogenesis, decreased protein synthesis and changes in splanchnic fuel selection, while changes in the rate of gluconeogenesis does not seem to play a significant role.
Simonsen
Lene
L
Department of Clinical Physiology/Nuclear Medicine, Bispebjerg Hospital, Copenhagen, Denmark. lr01@bbh.hosp.dk
Coker
Robert
R
A  L  Mulla
Nariman
N
Kjaer
Michael
M
Bülow
Jens
J
D000328:Adult; D004359:Drug Therapy, Combination; D005260:Female; D005934:Glucagon / Q000494:pharmacology*; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D015282:Octreotide / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D013152:Splanchnic Circulation / Q000187:drug effects* / Q000502:physiology
D007328:Insulin; D005934:Glucagon; D015282:Octreotide