Chelikani Prasanth K, Haver Alvin C, Reidelberger Roger D
Department of Veterans Affairs, Nebraska Western Iowa Health Care System, Research Service (151), 4101 Woolworth Ave., Omaha, NE 68105, USA.
Diabetes. 2006 Nov;55(11):3038-46. doi: 10.2337/db06-0730.
Ghrelin stimulates, while glucagon-like peptide-1 (GLP-1) and peptide YY(3-36) [PYY(3-36)] inhibit, food intake and gastric emptying in rats. We determined the dose-dependent effects of a 3-h intravenous infusion of ghrelin at dark onset on food intake in freely feeding rats, and on the inhibitory effects of intravenous infusion of GLP-1 and PYY(3-36) on food intake and gastric emptying. Ghrelin (150 pmol x kg(-1) x min(-1)) stimulated food intake by 28% during the infusion period primarily by increasing meal frequency; doses of 15 and 50 pmol x kg(-1) x min(-1) had no effect. GLP-1 (15 pmol x kg(-1) x min(-1)) inhibited food intake by 35-54%; coinfusion of ghrelin at 50 and 150 pmol x kg(-1) x min(-1) attenuated this effect by 60 and 64%, respectively. PYY(3-36) (15 pmol x kg(-1) x min(-1)) inhibited food intake by 32%; ghrelin at 15 and 50 pmol x kg(-1) x min(-1) attenuated this effect by 54 and 74%, respectively. A 20-min intravenous infusion of ghrelin (15-150 pmol x kg(-1) x min(-1)) attenuated GLP-1-and PYY(3-36)-induced inhibition of gastric emptying of saline by 6-29%. Thus, intravenous infusion of ghrelin during the early dark period stimulates food intake in freely feeding rats by increasing meal frequency, and similar doses of ghrelin attenuate gastric emptying and feeding responses to GLP-1 and PYY(3-36). These results suggest that ghrelin may stimulate food intake in part by attenuating the inhibitory effects of GLP-1 and PYY(3-36) on gastric emptying and food intake.
胃饥饿素具有促进作用，而胰高血糖素样肽 -1（GLP -1）和肽YY（3 - 36）[PYY（3 - 36）]则具有抑制作用，它们会影响大鼠的食物摄取和胃排空。我们测定了在黑暗开始时静脉输注3小时胃饥饿素对自由进食大鼠食物摄取的剂量依赖性影响，以及静脉输注GLP -1和PYY（3 - 36）对食物摄取和胃排空的抑制作用。胃饥饿素（150 pmol·kg⁻¹·min⁻¹）在输注期间使食物摄取量增加了28%，主要是通过增加进餐频率实现的；15和50 pmol·kg⁻¹·min⁻¹的剂量则没有效果。GLP -1（15 pmol·kg⁻¹·min⁻¹）使食物摄取量减少了35% - 54%；同时输注50和150 pmol·kg⁻¹·min⁻¹的胃饥饿素分别使这种作用减弱了60%和64%。PYY（3 - 36）（15 pmol·kg⁻¹·min⁻¹）使食物摄取量减少了32%；15和50 pmol·kg⁻¹·min⁻¹的胃饥饿素分别使这种作用减弱了54%和74%。静脉输注20分钟的胃饥饿素（15 - 150 pmol·kg⁻¹·min⁻¹）使GLP -1和PYY（3 - 36）诱导的生理盐水胃排空抑制作用减弱了6% - 29%。因此，在黑暗早期静脉输注胃饥饿素可通过增加进餐频率来刺激自由进食大鼠的食物摄取，并且相似剂量的胃饥饿素会减弱胃排空以及对GLP -1和PYY（3 - 36）的进食反应。这些结果表明，胃饥饿素可能部分通过减弱GLP -1和PYY（3 - 36）对胃排空和食物摄取的抑制作用来刺激食物摄取。
