Cayatte A J, Subbiah M T
Department of Internal Medicine and Pathology, University of Cincinnati Medical Center, OH 45267.
Atherosclerosis. 1989 Apr;76(2-3):131-8. doi: 10.1016/0021-9150(89)90096-8.
The relationship of fetal plasma cholesterol levels to aortic free and esterified cholesterol concentration was determined in the rabbit during gestation. Plasma cholesterol levels (mg/dl) in early fetuses were markedly high and decreased at term. While aortic free cholesterol content increased with fetal age, cholesteryl ester concentration did not change significantly and no pathological accumulation was evident. This occurred despite high fetal aortic cholesterol esterification activity noted in earlier studies. We evaluated the potential effect of rabbit placental extracts on lipid metabolism and cellular proliferation in fetal aortic explants to explore the role of placental factors in affecting lipid metabolism. Labeled [14C]oleate and [3H]thymidine were used to investigate the rates of incorporation of (a) oleate into lipids, and (b) thymidine into DNA, respectively. Placental extracts at term (but not from 22 days gestation) significantly decreased oleate incorporation (P less than 0.05) into cholesteryl esters, phospholipids and diglycerides. This effect of placental extracts was noted both in absence or presence of serum in the culture medium, and was predominantly found in fraction of Mr greater than 100,000. [3H]Thymidine incorporation (dpm/g protein) into DNA was significantly decreased (P less than 0.01) by placental extracts. These studies suggest that placental extracts contain factor(s) influencing fetal aortic lipid metabolism in culture.
在妊娠期间测定了兔胎儿血浆胆固醇水平与主动脉游离胆固醇和胆固醇酯浓度之间的关系。早期胎儿的血浆胆固醇水平（毫克/分升）显著升高，并在足月时下降。虽然主动脉游离胆固醇含量随胎龄增加，但胆固醇酯浓度没有显著变化，也没有明显的病理蓄积。尽管早期研究中注意到胎儿主动脉胆固醇酯化活性较高，但仍出现这种情况。我们评估了兔胎盘提取物对胎儿主动脉外植体脂质代谢和细胞增殖的潜在影响，以探讨胎盘因素在影响脂质代谢中的作用。分别使用标记的[14C]油酸和[3H]胸苷来研究（a）油酸掺入脂质的速率，以及（b）胸苷掺入DNA的速率。足月胎盘提取物（而非妊娠22天的胎盘提取物）显著降低了油酸掺入胆固醇酯、磷脂和甘油二酯的速率（P小于0.05）。在培养基中有无血清的情况下均观察到胎盘提取物的这种作用，且主要存在于分子量大于100,000的部分中。胎盘提取物显著降低了[3H]胸苷掺入DNA的速率（每分钟计数/克蛋白质，P小于0.01）。这些研究表明，胎盘提取物含有影响培养中胎儿主动脉脂质代谢的因子。
