Roux-en-Y gastric bypass (GB) surgery and sleeve gastrectomy (SG) improve glucose tolerance, in part, by enhancing prandial insulin levels. Post-meal hyperinsulinemia after GB is caused by larger insulin secretion and lower metabolic clearance rate of insulin (MCRI) . Reduced prandial MCRI after GB is exaggerated in those with post-GB complication of hypoglycemia, suggesting that altered MCRI is a pathogenic factor. We investigated the role of GB or SG on insulin kinetics in fasting and fed states.
The MCRI were measured during a mixed meal text (MMT) in 9 GB and 7 SG subjects: and during MMT combined with hyperinsulinemic hypoglycemic clamp in 9 GB, 7 SG, and 5 CN. Three groups were matched for age and BMI and surgical groups for time and weight loss since surgery; none had diabetes or liver disease.
Fasting MCRI was greater in GB and SC than CN (p<0.05) . Meal ingestion diminished MCRI to a larger extent in GB subjects compared to SG reaching nadir values in 20-50 min (relative reduction in GB vs. SG: 82±3% vs. 74±3%, p<0.05) . The relative postprandial reduction in MCRI was inversely associated with the glycemic excursion and insulin response. During the clamp hepatic insulin clearance was larger in GB and SG compared to CN (p<0.05) . There was no association between hepatic insulin clearance and peripheral insulin sensitivity (M/I) . Induced hyperinsulinemia approximating 300 µU/ml reduced MCRI in 3 groups despite a larger M/I in surgical subjects. Meal ingestion during hyperinsulinemic hypoglycemia clamp raised MCRI in 3 groups (p<0.05) returning to pre-meal values in an hour. These findings demonstrate that the differences in basal MCRI among GB, SG and CN are mainly attributed to variations in insulin clearance in the liver and independent on peripheral insulin sensitivity. Further, prandial reduction in MCRI is greater after GB than SG in proportion to the rates of nutrient influx.; the effect of nutrient ingestion on insulin kinetics is altered during hyperinsulinemic hypoglycemia.
M.S.Rayas: None. R.A.Defronzo: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Intarcia Therapeutics, Inc., Novo Nordisk, Research Support; AstraZeneca, Boehringer Ingelheim International GmbH, Merck & Co., Inc., Speaker's Bureau; AstraZeneca. A.Gastaldelli: Advisory Panel; Boehringer Ingelheim International GmbH, Novo Nordisk, Consultant; Boehringer Ingelheim International GmbH, Inventiva Pharma, Other Relationship; Eli Lilly and Company, Gilead Sciences, Inc., Pfizer Inc., Speaker's Bureau; Novo Nordisk. M.Salehi: None.
National Institute of Diabetes, Digestive, and Kidney Diseases (DK105379)