Yago María D, Díaz Ricardo J, Martínez María A, Audi Nama'a, Naranjo José A, Martínez-Victoria Emilio, Mañas Mariano
Departamento de Fisiología, Instituto de Nutrición y Tecnología de Alimentos, Universidad de Granada, Spain.
J Nutr Biochem. 2006 Apr;17(4):242-9. doi: 10.1016/j.jnutbio.2005.04.009. Epub 2005 May 31.
Olive oil is a major component of the Mediterranean diet, and its role in human health is being actively debated. This study aimed to clarify the mechanism of pancreatic adaptation to dietary fat. For this purpose, we examined whether dietary-induced modification of pancreatic membranes affects acinar cell function in response to the secretagogue acetylcholine (ACh). Weaning male Wistar rats were assigned to one of two experimental groups and fed for 8 weeks with a commercial chow (C) or a semisynthetic diet containing virgin olive oil as dietary fat (OO). The fatty acid composition of pancreatic plasma membranes was determined by gas-liquid chromatography. For assessment of secretory function, viable acini were incubated with ACh and amylase of supernatant was further assayed with a substrate reagent. Changes in cytosolic Ca(2+) concentration in response to ACh were measured by fura-2 AM fluorimetry. Compared to C rats, pancreatic cell membranes of OO rats had a higher level of monounsaturated fatty acids and a lower level of both saturated and polyunsaturated fatty acids, thus, reflecting the type of dietary fat given. Net amylase secretion in response to ACh was greatly enhanced after OO feeding, although this was not paralleled by enhancement of ACh-evoked Ca(2+) peak increases. In conclusion, chronic intake of diets that differ in the fat type influences not only the fatty acid composition of rat pancreatic membranes but also the responsiveness of acinar cells to ACh. This mechanism may be, at least in part, responsible for the adaptation of the exocrine pancreas to the type of fat available.
橄榄油是地中海饮食的主要成分，其在人类健康中的作用正受到积极讨论。本研究旨在阐明胰腺对膳食脂肪的适应机制。为此，我们研究了膳食诱导的胰腺膜改变是否会影响腺泡细胞对促分泌剂乙酰胆碱（ACh）的反应功能。将断乳雄性Wistar大鼠分为两个实验组之一，分别用市售饲料（C组）或含初榨橄榄油作为膳食脂肪的半合成饲料（OO组）喂养8周。通过气液色谱法测定胰腺质膜的脂肪酸组成。为评估分泌功能，将活的腺泡与ACh一起孵育，并用底物试剂进一步检测上清液中的淀粉酶。用fura-2 AM荧光法测量ACh刺激后胞质Ca(2+)浓度的变化。与C组大鼠相比，OO组大鼠的胰腺细胞膜单不饱和脂肪酸水平较高，饱和脂肪酸和多不饱和脂肪酸水平较低，这反映了所给予的膳食脂肪类型。OO组喂养后，ACh刺激引起的淀粉酶净分泌显著增强，尽管ACh诱发的Ca(2+)峰值增加并未相应增强。总之，长期摄入脂肪类型不同的饮食不仅会影响大鼠胰腺膜的脂肪酸组成，还会影响腺泡细胞对ACh的反应性。这种机制可能至少部分地解释了外分泌胰腺对可用脂肪类型的适应性。
