| Autor: |
Asare-Bediako I; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Paszkiewicz RL; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Kim SP; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Woolcott OO; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Kolka CM; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Burch M; Cedars-Sinai Medical Center, Department of Surgery , Los Angeles, California., Kabir M; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Piccinini F; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California., Bergman RN; Cedars-Sinai Diabetes and Obesity Research Institute , Los Angeles, California. |
| Abstrakt: |
Hyperinsulinemia, accompanied by reduced first-pass hepatic insulin extraction (FPE) and increased secretion, is a primary response to insulin resistance. Different in vivo methods are used to estimate the clearance of insulin, which is assumed to reflect FPE. We compared two methodologically different but commonly used indirect estimates with directly measured FPE in healthy dogs ( n = 9). The indirect methods were 1) metabolic clearance rate of insulin (MCR) during the hyperinsulinemic-euglycemic clamp (EGC), a steady-state method, and 2) fractional clearance rate of insulin (FCR) during the frequently sampled intravenous glucose tolerance test (FSIGT), a dynamic method. MCR was calculated as the ratio of insulin infusion rate to steady-state plasma insulin. FCR was calculated as the exponential decay rate constant of the injected insulin. Directly measured FPE is based on the difference in insulin measurements during intraportal vs. peripheral vein insulin infusions. We found a strong correlation between indirect FCR (min -1 ) and FPE (%). In contrast, we observed a poor association between MCR (ml·min -1 ·kg -1 ) and FPE (%). Our findings in canines suggest that FCR measured during FSIGT can be used to estimate FPE. However, MCR calculated during EGC appears to be a poor surrogate for FPE. |
