Ballantyne Garth H
Director of Minimally Invasive and Telerobotic Surgery, Hackensack University Medical Center, Hackensack, NJ 07601, USA.
Obes Surg. 2006 Jun;16(6):795-803. doi: 10.1381/096089206777346619.
Peptide YY (PYY) is secreted as a 36 amino acid, straight chain polypeptide, and is found in greatest concentrations in the terminal ileum, colon and rectum. After secretion, dipeptidyl peptidase IV (DPP-IV) cleaves the N-terminal Tyrosine-Proline residues from PYY(1-36), producing PYY(3-36). PYY(1-36) acts at all four human Y receptors, Y1, Y2, Y4 and Y5, while PYY(336) is a specific Y2 receptor agonist. PYY participates in the regulation of appetite and weight balance through hypothalamic-based mechanisms. PYY(1-36) stimulates appetite and weight gain through Y1 and Y5 receptors. PYY(3-36) suppresses appetite and stimulates weight loss through Y2 receptors. GI diseases that cause malabsorption increase both basal and meal-stimulated PYY levels. In contrast, obesity decreases both basal and meal-stimulated PYY levels. Mutations in the human PYY and Y2 receptor genes may contribute to the development of obesity. Small bowel resection elevates PYY levels in humans. Colon resections increase PYY levels in animal models but not in man. PYY changes following bariatric operations are incompletely studied. Vertical banded gastroplasty, open Roux-en-Y gastric bypass and jejunoileal bypass significantly elevate basal and meal-stimulated PYY levels. In dogs with Pavlov pouches, Roux-en-Y duodenojejunostomy (duodenal switch) increases PYY levels compared to Roux-en-Y gastrojejunostomy. DPP-IV activity is increased in obese individuals and remains increased after biliopancreatic diversion. Thus, diseases or operations which cause malabsorption, elevate basal and meal-stimulated PYY levels. Bariatric operations also increase basal and meal-stimulated PYY levels. This suggests that the combination of increased PYY levels and elevated levels of DPP-IV observed after bariatric operations may generate increased circulating levels of PYY(3-36), leading to hypothalamic-mediated suppression of appetite and promotion of weight loss through Y2 receptor mediated mechanisms.
肽YY（PYY）作为一种由36个氨基酸组成的直链多肽分泌，在回肠末端、结肠和直肠中浓度最高。分泌后，二肽基肽酶IV（DPP-IV）从PYY（1-36）上切割掉N端的酪氨酸-脯氨酸残基，产生PYY（3-36）。PYY（1-36）作用于所有四种人类Y受体，即Y1、Y2、Y4和Y5，而PYY（3-36）是一种特异性Y2受体激动剂。PYY通过基于下丘脑的机制参与食欲和体重平衡的调节。PYY（1-36）通过Y1和Y5受体刺激食欲和体重增加。PYY（3-36）通过Y2受体抑制食欲并刺激体重减轻。导致吸收不良的胃肠道疾病会使基础和餐后刺激的PYY水平升高。相比之下，肥胖会降低基础和餐后刺激的PYY水平。人类PYY和Y2受体基因的突变可能有助于肥胖的发生。小肠切除会使人类的PYY水平升高。结肠切除在动物模型中会增加PYY水平，但在人类中不会。减肥手术后PYY的变化尚未得到充分研究。垂直绑带胃成形术、开放式Roux-en-Y胃旁路术和空肠回肠旁路术会显著提高基础和餐后刺激的PYY水平。在患有巴甫洛夫袋的狗中，与Roux-en-Y胃空肠吻合术相比，Roux-en-Y十二指肠空肠吻合术（十二指肠转位术）会增加PYY水平。肥胖个体的DPP-IV活性增加，在胆胰分流术后仍保持增加。因此，导致吸收不良的疾病或手术会提高基础和餐后刺激的PYY水平。减肥手术也会增加基础和餐后刺激的PYY水平。这表明减肥手术后观察到的PYY水平升高和DPP-IV水平升高的组合可能会导致循环中PYY（3-3）水平升高，通过Y2受体介导的机制导致下丘脑介导的食欲抑制和体重减轻促进。
