Short-term regulation of peptide YY secretion by a mixed meal or peritoneal glucose-based dialysate in patients with chronic renal failure.

Background: Malnutrition is very prevalent among patients with chronic renal failure. The role of derangements in the gut-brain axis for regulation of appetite in the genesis of anorexia of these patients has not been adequately investigated. Design. Following a randomized, crossover design, we analysed plasma levels of peptide YY (PYY)(1-36) and PYY(3-36) both fasting and after a standardized oral mixed meal or intraperitoneal glucose infusion in 10 stable uraemic patients undergoing peritoneal dialysis and 8 healthy controls, matched for age, gender and body mass index. Main results. Median baseline plasma levels of PYY(1-36) in the different provocation tests oscillated between 406 and 460 pg/mL in patients, as compared with 73 and 100 pg/mL in controls (P < 0.001). Corresponding values for PYY(3-36) oscillated between 235 and 267 pg/mL in patients, versus 56 and 70 pg/mL in controls (P < 0.001). The association of high levels of PYY(3-36) and normal levels of acylated ghrelin (when compared with healthy controls) configurated a markedly pro-anorexigenic pattern in patients. Neither oral intake nor intraperitoneal glucose resulted in significant changes in plasma levels of PYY(1-36) or PYY(3-36) in subjects with renal failure, in contrast with the expected postprandial rise observed in healthy controls (41% for PYY(1-36), P = 0.04 and 32% for PYY(3-36), P = 0.02, median values).
Conclusions: Baseline plasma levels of PYY(1-36) or PYY(3-36) are markedly elevated in patients with renal failure undergoing peritoneal dialysis. Provocation studies disclose a marked disregulation in the postprandial secretion of these anorexigenic peptides, when compared with healthy controls. These findings may contribute to clarify the complex pathogenesis of anorexia of chronic renal failure.