title: Effects of ingestion routes on hormonal and metabolic profiles in gastric-bypassed humans.
abstract: BACKGROUND
  Gastric bypass surgery (GBP) results in the rapid resolution of type 2 diabetes. Most studies aiming to explain the underlying mechanisms are limited to data obtained after a postsurgical recovery period, making assessment of confounding influences from, for example, weight loss and altered nutrient intake difficult.
  
  
  OBJECTIVE
  To examine the impact of GBP on hormonal and metabolite profiles under conditions of identical nutrient intake independent of weight loss, we studied GBP patients fitted with a gastrostomy tube to enable the administration of nutrients to bypassed segments of the gut. Thus, this model allowed us to simulate partially the preoperative condition and compare this with the postoperative situation in the same patient.
  
  
  METHODS
  Patients (n = 4) were first given a mixed meal test (MMT) orally and then via the gastrostomy tube, preceded by overnight and 2-hour fasting, respectively. Blood samples were assessed for hormones and metabolites.
  
  
  RESULTS
  The oral MMT yielded 4.6-fold increase in plasma insulin (P < .05), 2-fold in glucagon-like peptide-1 (P < .05), and 2.5-fold in glucose-dependent insulinotropic peptide (P < .05) plasma levels, compared with the gastrostomy MMT. The changes in hormone levels were accompanied by elevated branched-chain amino acid levels (1.4-2-fold, P < .05) and suppressed fatty acid levels (∼50%, P < .05).
  
  
  CONCLUSIONS
  These data, comparing identical nutrient delivery, demonstrate markedly higher incretin and insulin responses after oral MMT than after gastric MMT, thereby providing a potential explanation for the rapid remission of type 2 diabetes observed after GBP. The simultaneous increase in branched-chain amino acid questions its role as a marker for insulin resistance.
authors: Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, SE-205 02 Malmö, Sweden.
authors: Andreas
authors: A
authors: Lindqvist
authors: Peter
authors: P
authors: Spégel
authors: Mikael
authors: M
authors: Ekelund
authors: Hindrik
authors: H
authors: Mulder
authors: Leif
authors: L
authors: Groop
authors: Jan
authors: J
authors: Hedenbro
authors: Nils
authors: N
authors: Wierup
mesh_terms: D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000517:prevention & control*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D015390:Gastric Bypass; D005749:Gastric Inhibitory Polypeptide / Q000097:blood; D005774:Gastrostomy; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D062407:Meals; D009767:Obesity, Morbid / Q000097:blood / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D019518:Postprandial Period
chemical_list: D000597:Amino Acids, Branched-Chain; D015415:Biomarkers; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1