REGULATION OF TRIGLYCERIDE COMPOSITION OF MILK

人类和其他物种的乳脂包括大量的 含有中链脂肪酸的甘油三酯，易于消化 并在新生儿的主要能量来源时， 脂质消化装置尚未完全成熟。 牛奶脂肪的摄入 新生儿引起轻度酮症;这些酮显然是重要的 大脑的生长和发育。 我们的计划是针对 阐明调节这种重要的生产的机制， 由乳腺提供营养。 我们已经证明，在大鼠、小鼠和人类中， 中链脂肪酸的生物合成需要两种关键酶， 酸性合成酶和硫酯酶II，一种哺乳动物特异性的链终止酶， 酵素 采用酶学和免疫组织化学技术 用胶原凝胶培养系统模拟乳腺癌的发生， 在大鼠、小鼠和人类中发生的催乳发育阶段， （一）确定乳腺癌的分化程序是否 人的脂肪生成系统更接近于大鼠， 其中脂肪酸合成酶和硫酯酶II被表达 异步地，或者鼠标，在鼠标中它们是同步表达的， (ii)确定多肽和甾体激素的需要量， 调节两种酶的诱导和维持，（iii）确定 蛋白质合成与降解在激素运动中的作用 脂肪生成系统的调节。 完全分化的乳腺上皮 从人乳中分离的细胞将被用于监测饮食的影响， 和泌乳阶段对乳脂合成过程的影响 哺乳期的人类乳房

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.