title: Is intestinal gluconeogenesis a key factor in the early changes in glucose homeostasis following gastric bypass?
abstract: BACKGROUND
  In 2008, Troy et al. hypothesised that under fasting conditions, intestinal gluconeogenesis generates glucose levels in the portal vein which trigger the portal sensor to change insulin resistance and that this mechanism contributes to the effects of Roux-en-Y gastric bypass (RYGB) surgery on type 2 diabetes mellitus (T2DM). In a recent paper, Kashyap et al. (Int J Obes 34(3):426-471, 2010) cited this hypothesis as a potential explanation for the early changes in insulin sensitivity and beta cell function seen after RYGB. We proposed a study to examine this possibility.
  
  
  METHODS
  We simultaneously sampled fasting portal venous blood and central venous blood in 28 patients (eight diabetics and 20 non-diabetics) before and again six days after RYGB surgery in morbidly obese patients, for measurement of glucose levels.
  
  
  RESULTS
  We found no significant difference in the glucose levels from the two sites either before or after RYGB in diabetic patients and a small, but significant difference in the post-operative glucose levels from non-diabetic patients (4.2 vs 4.0 mM, p < 0.0001).
  
  
  CONCLUSIONS
  Direct simultaneous measurement of fasting glucose in portal and central venous blood before and 6 days after RYGB provides no evidence to support the hypothesis that intestinal gluconeogenesis contributes to the resolution of T2DM seen after RYGB.
authors.affiliation: Wakefield Biomedical Research Unit, University of Otago, Wellington, New Zealand.
authors.forename: Mark Thomas
authors.initials: MT
authors.lastname: Hayes
authors.forename: Jonathan
authors.initials: J
authors.lastname: Foo
authors.forename: Vinko
authors.initials: V
authors.lastname: Besic
authors.forename: Yulia
authors.initials: Y
authors.lastname: Tychinskaya
authors.forename: Richard Strawson
authors.initials: RS
authors.lastname: Stubbs
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000601:surgery; D005260:Female; D015390:Gastric Bypass; D005943:Gluconeogenesis; D006706:Homeostasis; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery*; D011169:Portal Vein
chemical_list: D001786:Blood Glucose