The effect of a time delay on the characteristics of the canine glucoregulatory system
| Autor: | T.R. Strack, G.R. Greenberg, A.M. Albisser, Kenneth S. Polonsky |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Blood Glucose
Male medicine.medical_specialty Time Factors Endocrinology Diabetes and Metabolism medicine.medical_treatment chemistry.chemical_compound Endocrinology Dogs Internal medicine medicine Carnivora Animals Insulin Infusions Intravenous Pancreatic hormone biology business.industry C-peptide Portal Vein Fissipedia Metabolism Carbohydrate biology.organism_classification Glucose chemistry Blood sugar regulation business |
| Zdroj: | Metabolism: clinical and experimental. 39(12) |
| ISSN: | 0026-0495 |
| Popis: | In order to elucidate the effect of a relative time delay on glucose regulation, we performed experiments with differently timed infusions of insulin and glucose in a canine model. When portal insulin infusion (0.03 U/kg over 5 minutes) preceded portal glucose infusion (0.05 g/kg over 5 minutes) by 1 minute, glycemia increased to a maximum value of 104 ± 4 mg/dL at 6 minutes, whereas insulinemia peaked at 3 minutes at a level of 130 ± 4 μU/mL (baseline, 21 ± 7 μU/mL). C-peptide levels increased from 200 ± 50 to 270 ± 30 pmol/L. Glycemia then decreased to a minimum level of 61 ± 4 mg/dL, significantly lower (P < .02) than the corresponding values in control experiments when insulin was infused alone. With a reversed timing sequence of infusions with glucose infusion preceding insulin infusion by 1 minute, glycemia increased similarly, but decreased to a minimum level of only 84 ± 4 mg/dL, which was significantly higher (P < .01) than in the above experiment. Insulinemia peaked similarly at 126 ± 7 μU/mL, and C-peptide increased from 210 ± 50 to 280 ± 50 pmol/L. These experiments demonstrated an unexpected effect: adding glucose to an insulin infusion almost doubled the biological activity of the exogenous insulin as measured by its hypoglycemic action. They also indicated that small perturbations of glycemia and insulinemia in the portal circulation have a profound effect on metabolism, and that even short relative time delays in elevating either insulinemia or glycemia can cause significantly different metabolic outcomes. Under conditions when exogenous insulin preceded glucose infusion, glucose paradoxically enhanced the hypoglycemic activity of exogenous insulin without enhancing endogenous insulin secretion. |
| Databáze: | OpenAIRE |
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