Turley S D, Burns D K, Dietschy J M
Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75235-8887, USA.
Am J Physiol. 1998 Jun;274(6):E1099-105. doi: 10.1152/ajpendo.1998.274.6.E1099.
These studies used the suckling lamb as a model to determine the sources of cholesterol that are utilized for development of the central nervous system in the neonate. Lambs were studied at 1.3 and 16.4 days after birth. Over this 15-day interval, 14 g of new brain tissue were formed. About 9-10 mg of cholesterol were utilized daily for this new tissue growth. To determine the source of this cholesterol, the absolute rates of low-density lipoprotein clearance and cholesterol synthesis were measured in vivo in nine separate regions of the central nervous system. Low-density lipoprotein clearance throughout the brain was very low and at most could have contributed only 0.3-0.4 mg cholesterol daily for new brain growth. In contrast, the brain synthesized 7-8 mg of cholesterol/day. There were pronounced regional differences in the concentration of cholesterol throughout the brain, and these correlated closely with the rate of sterol synthesis (r = 0.95) in these same regions. We conclude that the principal source of sterol for brain growth in suckling lambs is de novo synthesis.
这些研究以哺乳羔羊为模型，来确定用于新生儿中枢神经系统发育的胆固醇来源。在出生后1.3天和16.4天对羔羊进行研究。在这15天的间隔期内，形成了14克新的脑组织。每天约有9 - 10毫克胆固醇用于这种新组织的生长。为了确定这种胆固醇的来源，在中枢神经系统的九个不同区域体内测量了低密度脂蛋白清除率和胆固醇合成的绝对速率。整个大脑的低密度脂蛋白清除率非常低，每天最多只能为新的脑生长贡献0.3 - 0.4毫克胆固醇。相比之下，大脑每天合成7 - 8毫克胆固醇。整个大脑中胆固醇浓度存在明显的区域差异，并且这些差异与这些相同区域中甾醇合成速率密切相关（r = 0.95）。我们得出结论，哺乳羔羊大脑生长的甾醇主要来源是从头合成。
