Improvement in peripheral glucose uptake after gastric bypass surgery is observed only after substantial weight loss has occurred and correlates with the magnitude of weight lost.
BACKGROUND
Altered gut and pancreatic hormone secretion may bolster resolution of insulin resistance after Roux-en-Y gastric bypass (RYGB), but the independent effects of weight loss and hormonal secretion on peripheral glucose disposal are unknown.


METHODS
Two groups of nondiabetic morbidly obese patients were studied: RYGB followed by standardized caloric restriction (RYGB, n = 12) or caloric restriction alone (diet, n = 10). Metabolic evaluations (euglycemic-hyperinsulinemic clamp, meal tolerance test) were done at baseline and 14 days (both groups) and 6 months after RYGB.


RESULTS
At baseline, body composition, fasting insulin, and glucose and peripheral glucose disposal did not differ between groups. At 14 days, excess weight loss (EWL) was similar (RYGB, 12.7% vs. diet, 10.9%; p = 0.12), fasting insulin and glucose decreased to a similar extent, and RYGB subjects had altered postmeal patterns of gut and pancreatic hormone secretion. However, peripheral glucose uptake (M value) was unchanged in both groups. Six months after RYGB, EWL was 49.7%. The changes in fasting glucose and insulin levels and gut hormone secretion persisted. M values improved significantly, and changes in M values correlated with the % EWL (r = 0.68, p = 0.02).


CONCLUSIONS
Improvement in peripheral glucose uptake following RYGB was observed only after substantial weight loss had occurred and correlated with the magnitude of weight lost.
Department of Surgery, University of California San Francisco, San Francisco, CA, USA. campos@surgery.wisc.edu
Guilherme M
GM
Campos
Charlotte
C
Rabl
Sofia
S
Peeva
Ruxandra
R
Ciovica
Madhu
M
Rao
Jean-Marc
JM
Schwarz
Peter
P
Havel
Morris
M
Schambelan
Kathleen
K
Mulligan
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition; D031204:Caloric Restriction; D005215:Fasting; D005260:Female; D015390:Gastric Bypass; D005749:Gastric Inhibitory Polypeptide / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000178:diet therapy / Q000601:surgery; D015431:Weight Loss
D001786:Blood Glucose; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1