Guan D, Green G M
Department of Physiology, University of Texas Health Science Center, San Antonio 78284-7756, USA.
Am J Physiol. 1996 Jul;271(1 Pt 1):G42-7. doi: 10.1152/ajpgi.1996.271.1.G42.
The importance of peptic digestion of dietary protein in pancreatic enzyme secretion and cholecystokinin (CCK) release was investigated in conscious rats. Native casein and native bovine serum albumin (BSA) were infused intragastrically and intra-intestinally, and the effect of peptic predigestion on the pancreatic secretory and plasma CCK responses to BSA were determined (all infused at 450 mg/h). When dietary proteins were infused intraduodenally, native casein was a much stronger stimulant of CCK release (5.8 +/- 0.6 vs. 1.6 +/- 0.2 pM) and pancreatic protein secretion [5,592 +/- 736 vs. 750 +/- 461 (0-180)mg.kg-1.min] than native BSA. Infusion by the intragastric route markedly increased pancreatic protein secretion for BSA but not for casein. HCl-pepsin treatment of BSA significantly increased its ability to increase pancreatic secretion and plasma CCK. Pancreatic protease binding to native BSA was inferior compared with casein. Peptic digestion of BSA increased its protease binding activity more than threefold. The results indicate that peptic digestion of dietary proteins enhances the proteins' ability to elicit the pancreatic feedback stimulatory response.
在清醒大鼠中研究了膳食蛋白质的胃消化在胰腺酶分泌和胆囊收缩素（CCK）释放中的重要性。将天然酪蛋白和天然牛血清白蛋白（BSA）分别经胃内和肠内输注，并测定胃消化对胰腺分泌和血浆CCK对BSA反应的影响（均以450 mg/h的速度输注）。当膳食蛋白质经十二指肠输注时，天然酪蛋白比天然BSA更能强烈刺激CCK释放（5.8±0.6对1.6±0.2 pM）和胰腺蛋白质分泌[5,592±736对750±461（0 - 180）mg·kg⁻¹·min]。经胃途径输注显著增加了BSA的胰腺蛋白质分泌，但对酪蛋白没有影响。用HCl-胃蛋白酶处理BSA显著增强了其增加胰腺分泌和血浆CCK的能力。与酪蛋白相比，胰腺蛋白酶与天然BSA的结合较差。胃消化使BSA的蛋白酶结合活性增加了三倍多。结果表明，膳食蛋白质的胃消化增强了蛋白质引发胰腺反馈刺激反应的能力。
