Anesthesia rapidly suppresses insulin pulse mass but enhances the orderliness of insulin secretory process.
Induction of anesthesia is accompanied by modest hyperglycemia and a decreased plasma insulin concentration. Most insulin is secreted in discrete pulses occurring at approximately 6- to 8-min intervals. We sought to test the hypothesis that anesthesia inhibits insulin release by disrupting pulsatile insulin secretion in a canine model by use of direct portal vein sampling. We report that induction of anesthesia causes an abrupt decrease in the insulin secretion rate (1.1 +/- 0.2 vs. 0.7 +/- 0.1 pmol. kg(-1). min(-1), P < 0.05) by suppressing insulin pulse mass (630 +/- 121 vs. 270 +/- 31 pmol, P < 0.01). Anesthesia also elicited an approximately 30% higher increase in insulin pulse frequency (P < 0.01) and more orderly insulin concentration profiles (P < 0.01). These effects were evoked by either sodium thiamylal or nitrous oxide and isoflurane. In conclusion, anesthesia represses insulin secretion through the mechanism of a twofold blunting of pulse mass despite an increase in orderly pulse frequency. These data thus unveil independent amplitude and frequency controls of beta-cells' secretory activity in vivo.
Vore
S J
SJ
Department of Comparative Medicine, East Carolina School of Medicine, Greenville, North Carolina 27858, USA.
Aycock
E D
ED
Veldhuis
J D
JD
Butler
P C
PC
D000758:Anesthesia; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002406:Catheterization, Peripheral; D004285:Dogs; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007530:Isoflurane / Q000494:pharmacology; D009609:Nitrous Oxide / Q000494:pharmacology; D011169:Portal Vein / Q000502:physiology; D013840:Thiamylal / Q000494:pharmacology
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D001786:Blood Glucose; D007328:Insulin; D013840:Thiamylal; D007530:Isoflurane; D009609:Nitrous Oxide