REGULATION OF TRIGLYCERIDE COMPOSITION OF MILK

人类和其他物种的乳脂包括大量的 甘油三酯含有中链脂肪酸，易于消化 并为新生儿提供主要的能量来源 脂肪消化装置还没有完全成熟。乳脂的摄入 由新生儿引起的轻度酮症；这些酮显然是重要的 对于大脑的生长和发育来说。我们的节目针对的是 阐明调控这一重要物质产生的机制 由乳房提供营养。我们已经证明，在大鼠、小鼠和人类身上， 中链脂肪酸的生物合成需要两种关键酶，脂肪 酸性合成酶和硫代酯酶II，一种乳腺特异的链终止物 酵素。同时使用酶学和免疫组织化学技术 用胶原胶培养系统模拟乳房和 在大鼠、小鼠和人类中发生的产乳发育阶段，我们 将：(I)确定乳腺分化方案是否 人类的脂肪生成系统与大鼠的脂肪生成系统更相似， 表达哪种脂肪酸合成酶和硫代酯酶II 异步的，或者说鼠标，在其中同步表达它们， (Ii)确定中国对多肽和类固醇激素的需要量 调节两种酶的诱导和维持，(III)测定 蛋白质合成和降解在荷尔蒙运动中的作用 对造脂系统的调节。完全分化的乳腺上皮 从母乳中分离出的细胞将被用来监测饮食的效果 哺乳阶段对乳脂合成过程的影响 哺乳人的乳房。

Milk fat of humans and other species includes significant quantities of triglycerides containing medium chain fatty acids, is readily digestible and provides the neonate with a major energy source at a time when its lipid-digesting apparatus has not fully matured. The ingestion of milk fat by neonates induces a mild ketosis; these ketones are apparently important for growth and development of the brain. Our program is directed toward elucidating the mechanisms which regulate the production of this important nutrient by mammay gland. We have shown that in rats, mice and humans, the biosyntesis of medium chain fatty acids requires two key enzymes, fatty acid synthetase and thioesterase II, a mammary-specific, chain-terminating enzyme. Employing both enzymological and immunohistochemical techniques with collagen gel culture systems that simulate the mammogenic and lactogenic phases of development occurring in rats, mice and humans, we will: (i) determine whether the program of differentiation of the mammary lipogenic system of the human resembles more closely that of the rat, in which fatty acid synthetase and thioesterase II are expressed asynchronously, or the mouse, in which they are expressed synchronously, (ii) determine the requirement for polypeptide and steriod hormones in regulating induction and maintenance of the two enzymes, (iii) determine the role of protein synthesis and degradatio in the exercising of hormonal regulation of the lipogenic system. Fully differentated mammary epithelial cells isolated from human milk will be used to monitor the effects of diet and stage of lactation on the process of milk fat synthesis in the lactating human breast.