Walters J R, Horvath P J, Weiser M M
Gastroenterology. 1986 Jul;91(1):34-40. doi: 10.1016/0016-5085(86)90435-x.
Basolateral, brush-border, and Golgi-enriched subcellular membrane fractions, prepared from homogenates of rat small intestinal mucosa obtained by scraping, had unusually high concentrations of nonesterified fatty acids. These fatty acids appear to be responsible for the large amount of calcium binding, an effect that previously was shown to be reduced in vitamin D deficiency. In contrast, basolateral and Golgi membranes prepared from isolated cells had low levels of nonesterified fatty acids and calcium binding. Intermediate levels were found with isolated cells that were not put through the usual washing procedures. Addition to homogenates of scrapings of a lipase inhibitor, diethyl-p-nitrophenyl phosphate, reduced calcium binding and nonesterified fatty acids to levels similar to those in membranes prepared from isolated cells. Phospholipase A activity was low in homogenates of isolated cells and high in scrapings; this was reduced in intestinal scrapings of vitamin D-deficient rats. Ileal membranes had more calcium binding than duodenal membranes, and ileal homogenates also had greater phospholipase A activity. Preparation of subcellular membranes from rat intestinal scrapings can result in altered lipid composition, probably due to lipolytic enzyme activity; in addition to increasing cation-binding, these high levels of fatty acids may affect other membrane properties and enzyme function.
通过刮取获得的大鼠小肠黏膜匀浆制备的基底外侧、刷状缘和富含高尔基体的亚细胞膜组分，具有异常高浓度的非酯化脂肪酸。这些脂肪酸似乎是大量钙结合的原因，此前已表明维生素D缺乏时这种效应会降低。相比之下，从分离细胞制备的基底外侧膜和高尔基体膜的非酯化脂肪酸水平和钙结合水平较低。未经过常规洗涤程序的分离细胞呈现出中间水平。向刮取物匀浆中添加脂肪酶抑制剂对硝基苯基磷酸二乙酯，可将钙结合和非酯化脂肪酸降低至与从分离细胞制备的膜中相似的水平。分离细胞匀浆中的磷脂酶A活性较低，刮取物中的活性较高；维生素D缺乏大鼠的肠道刮取物中该活性降低。回肠膜的钙结合能力比十二指肠膜更强，回肠匀浆的磷脂酶A活性也更高。从大鼠肠道刮取物制备亚细胞膜可能会导致脂质组成改变，这可能是由于脂解酶活性所致；除了增加阳离子结合外，这些高水平的脂肪酸可能会影响其他膜特性和酶功能。
