文章基本信息

标题：Origin of milk cholesterol in the rat: dietary versus endogenous sources
本地全文：下载
作者：R. Clarenburg ; I. L. Chaikoff
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1966
卷号：7
期号：1
页码：27-37
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Slices of mammary gland from lactating rats, incubated with acetate-1-¹⁴C or mevalonate-2-¹⁴C, synthesized cholesterol-¹⁴C. Within 2 min of an intravenous injection of 1 ml of a suspension of chylomicrons containing cho1esterol-4-¹⁴C, mammary glands of lactating rats removed as much as 29%, of the labeled cholesterol; those of 2-day-postlactating rats removed none. Rats were fed a diet containing 0.05% cholesterol-4-¹⁴C from 7 days prepartum to 20 days postpartum. At isotopic equilibrium, the relative specific activities of milk and dietary cholesterol indicated a dietary origin for 11% of the milk cholesterol. The extent to which endogenous sources—liver and mammary gland—contributed cholesterol to milk proved entirely dependent on whether dietary cholesterol, in the form of chyle lipoproteins, was first processed by liver or taken up directly by mammary gland. Lack of information regarding the extent to which chyle cholesterol is removed from blood under physiological conditions by mammary gland and other tissues precludes precise assessment of the endogenous contributions to milk cholesterol and, moreover, casts doubt on the quantitative interpretability of cholesterol-¹⁴C-feeding experiments reported in the literature.
关键词：lactation ; rat ; mammary gland ; cholesterol ; biosynthesis ; uptake ; chylomicron ; dietary ; cholesterol-4-¹⁴C ; liver ; isotopic equilibrium ; difficulties ; interpretation