Plasma glucose and insulin regulation is abnormal following gastric bypass surgery with or without neuroglycopenia.
BACKGROUND
Enhanced insulin sensitivity is commonly seen following Roux-en-Y gastric bypass surgery (RYGB) whereas symptomatic hypoglycemia post-RYGB seems to occur infrequently. It is unclear how different plasma glucose and insulin responses are in patients with symptomatic hypoglycemia (SX-RYGB) versus those who remain asymptomatic (ASX-RYGB), nor when compared with non-surgical controls with varying degrees of insulin sensitivity.


METHODS
Plasma glucose and insulin concentrations were determined following a 75-g oral glucose challenge in five groups: symptomatic and asymptomatic patients following RYGB (n = 9 each) and overweight/obese controls, divided into three subgroups (n = 30 each) on the basis of degree of insulin sensitivity measured by the insulin suppression test.


RESULTS
SX-RYGB group had higher 30-min glucose after oral glucose compared with the ASX-RYGB group (p = 0.04). The two groups did not differ in peak glucose and insulin concentrations, nadir glucose concentration, or insulin-to-glucose ratio 30 min after oral glucose. These values were significantly different from the three control groups, and peak insulin concentrations post-RYGB were increased at every degree of insulin sensitivity as compared with the control groups.


CONCLUSIONS
Plasma glucose and insulin responses to oral glucose in patients with symptomatic hypoglycemia post-RYGB are minimally different when compared to individuals who remain asymptomatic, and both groups demonstrate hyperinsulinemia out of proportion to their degree of insulin sensitivity.
Kim
Sun H
SH
Department of Medicine, Stanford University Medical Center, 300 Pasteur Drive, Room S025, Stanford, CA 94305-5103, USA. sunhkim@stanford.edu
Liu
Teresa C
TC
Abbasi
Fahim
F
Lamendola
Cindy
C
Morton
John M
JM
Reaven
Gerald M
GM
McLaughlin
Tracey L
TL
D000328:Adult; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D015390:Gastric Bypass; D005951:Glucose Tolerance Test; D006801:Humans; D006946:Hyperinsulinism / Q000453:epidemiology* / Q000209:etiology; D007003:Hypoglycemia / Q000453:epidemiology* / Q000209:etiology; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery
D001786:Blood Glucose; D007328:Insulin