Effects of Roux-en-Y Bypass on Ghrelin, PYY and Insulin
How Stomach Bypass Affects Biochemistry of the Body
| Bariatric Surgery information Effects of Roux-en-Y Bypass on Ghrelin, PYY and Insulin |
How Stomach Bypass Affects Biochemistry of the Body |
Guide to Weight Loss Surgery - Research Into Gastric Reduction Surgery |
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Effects of Roux-en-Y Gastric Bypass Surgery on Fasting and Postprandial Concentrations of Plasma Ghrelin, PYY and Insulin Method To help understand the mechanisms by which weight loss after Roux-en-Y gastric bypass (RYGBP) is maintained, we measured circulating concentrations of total and bioactive octanoylated ghrelin, Peptide YY (PYY), glucose and insulin in the fasted state and in response to a liquid test meal in three groups of adult women: lean; weight-stable 35 ± 5 months after RYGBP; and matched to the surgical group for body mass index and age (n = 12). Results Fasting plasma total ghrelin levels were nearly identical between Roux-en-Y Gastric Bypass Surgery and the matched controls, and highest in lean controls. The response to the test meal was comparable between lean and Roux-en-Y Gastric Bypass Surgery groups with 27% and 20% maximal suppression, respectively, whereas the magnitude of suppression was significantly diminished in the matched controls (17%) compared with the lean group. Fasting levels of octanoylated ghrelin were highest in the lean controls 220 ± 36 pg/ml vs. 143 ± 27 in the RYGBP group and 127 ± 12 pg/ml in the matched controls (P < 0.05). The magnitude of maximal post-meal suppression of octanolyated ghrelin was more marked than with total ghrelin, but similar among groups, ranging from 44 - 47%. In response to the test meal, there was an early exaggerated rise in PYY in the RYGBP group, such that the peak PYY concentration was 163 ± 24 pg/ml compared with 58 ± 17 and 77 ± 23 in the matched and lean controls, respectively; area under the curve at 90 min was significantly greater compared with both control groups. Leptin and fasting insulin concentrations and HOMA IR indices were nearly identical between lean and Roux-en-Y Gastric Bypass Surgery subjects, and significantly higher in the BMI-matched controls. Summary The absence of a compensatory increase in ghrelin concentrations that usually occurs with diet-induced weight loss, and the exaggerated postprandial PYY response after Roux-en-Y Gastric Bypass Surgery, may contribute to weight loss and to the ability of an individual to maintain weight loss after this surgical procedure. Authors: Source: Gastric Bypass Surgery Information |