Gacs G, Barltrop D
Gut. 1977 Jan;18(1):64-8. doi: 10.1136/gut.18.1.64.
The significance of calcium soap formation in the inhibition of calcium absorption has been studied in rats. 47Ca labelled soaps of fatty acids were introduced into the duodenum and the absorption of calcium measured after four hours in a whole body counter. The absorption of calcium was inversely correlated with the chain length of the fatty acid varying from 1% for Ca-stearate to 60% for Ca-hexanoate. Increasing the degree of unsaturation of the fatty acid was accompanied by increased calcium absorption. The availability of calcium for absorption from the soaps was correlated with their solubility in 1% aqueous Na-tauroglycocholate. The percentages of calcium as soap in the small intestine and the faeces after intragastric administration of calcium and fats were similar, which suggests that the faecal content of calcium soaps is an index of intestinal soap formation. Soap formation was negligible when CaCl2 was given with tristearate, triolaeate, or tridecanoate and no depression of calcium absorption was observed. Calcium absorption was markedly impaired by the addition of phosphates at a Ca/P ratio of 1:1 irrespective of the presence of neutral fats. Stearic acid resulted in significant soap formation and reduced calcium absorption. The degree of Ca-soap formation and the inhibition of calcium absorption were well correlated. The results suggest that, although calcium soap formation may markedly depress calcium absorption in the rat, no significant soap formation takes place when fats are given in the form of triglycerides.
在大鼠身上研究了钙皂形成对钙吸收抑制作用的意义。将47Ca标记的脂肪酸皂引入十二指肠，并在全身计数器中4小时后测量钙的吸收。钙的吸收与脂肪酸链长度呈负相关，从硬脂酸钙的1%到己酸钙的60%不等。脂肪酸不饱和度的增加伴随着钙吸收的增加。从皂中吸收钙的可用性与其在1%牛磺胆酸钠水溶液中的溶解度相关。胃内给予钙和脂肪后，小肠和粪便中以皂形式存在的钙的百分比相似，这表明粪便中钙皂的含量是肠道皂形成的一个指标。当氯化钙与硬脂酸三酯、油酸三酯或十三烷酸三酯一起给予时，皂的形成可以忽略不计，并且未观察到钙吸收的降低。无论是否存在中性脂肪，当钙/磷比为1:1时添加磷酸盐都会显著损害钙的吸收。硬脂酸导致显著的皂形成并降低钙吸收。钙皂形成的程度与钙吸收的抑制作用密切相关。结果表明，虽然钙皂形成可能会显著降低大鼠的钙吸收，但当以甘油三酯形式给予脂肪时，不会发生显著的皂形成。
