Plonné D, Stacke A, Weber K U, Endisch U, Dargel R
Institute of Pathobiochemistry, Friedrich-Schiller University Jena, Germany.
Biochim Biophys Acta. 1996 Jan 5;1299(1):54-66. doi: 10.1016/0005-2760(95)00189-1.
Explants of visceral rat yolk sacs from gestational days 16, 18 and 22 were used for studying developmental changes of secretion and density distribution of lipoproteins, particularly of those containing apoB. Moreover, the influence of fatty acid supply on the amount and density distribution of secreted apolipoproteins was studied on day 18 of gestation. Active lipoprotein production was observed in yolk sacs taken on days 16 and 18 of gestation. It declined considerably on day 22 of gestation in parallel with the production of total protein, triacylglycerols and cholesterol. On all gestational days, apoB floated mainly in the LDL range ( > or = 70%) with differences in the distribution pattern of LDL subclasses. The lowest density of secreted LDL was found on day 18 of gestation (peak at d = 1.025 g/ml) followed by day 16 (peak at d = 1.035 g/ml) and day 22 of gestation (peak at d = 1.045 g/ml). ApoAIV, apoE and apoAI floated exclusively in the HDL range with a peak at d = 1.089 g/ml independently of the gestational day. After incubation of yolk sacs from the 18th day of gestation with 0.4 mM or 0.8 mM oleate, the density of secreted apoB containing particles was decreased (peaks in the VLDL and IDL density range), whereas palmitate in the same concentrations caused a redistribution of secreted apoB toward higher densities (peaks at d > or = 1.032 g/ml). Taken together, the data provide evidence that the density of LDL subclasses produced by isolated yolk sacs between days 16 and 22 of gestation depended on the gestational stage. Moreover, addition of unsaturated or saturated fatty acids to the organ culture differently affected the secretory rate and the density of lipoproteins delivered by yolk sacs on day 18 of gestation.
取自妊娠第16、18和22天的大鼠内脏卵黄囊外植体用于研究脂蛋白分泌和密度分布的发育变化，尤其是含载脂蛋白B的脂蛋白。此外，在妊娠第18天研究了脂肪酸供应对分泌载脂蛋白数量和密度分布的影响。在妊娠第16和18天采集的卵黄囊中观察到了活跃的脂蛋白产生。在妊娠第22天，它与总蛋白、三酰甘油和胆固醇的产生同时大幅下降。在所有妊娠日，载脂蛋白B主要在低密度脂蛋白范围内漂浮（≥70%），低密度脂蛋白亚类的分布模式存在差异。分泌的低密度脂蛋白的最低密度在妊娠第18天（峰值在d = 1.025 g/ml），其次是第16天（峰值在d = 1.035 g/ml）和妊娠第22天（峰值在d = 1.045 g/ml）。载脂蛋白AIV、载脂蛋白E和载脂蛋白AI仅在高密度脂蛋白范围内漂浮，峰值在d = 1.089 g/ml，与妊娠日无关。将妊娠第18天的卵黄囊与0.4 mM或0.8 mM油酸孵育后，分泌的含载脂蛋白B颗粒的密度降低（峰值在极低密度脂蛋白和中间密度脂蛋白密度范围内），而相同浓度的棕榈酸导致分泌的载脂蛋白B向更高密度重新分布（峰值在d≥1.032 g/ml）。综上所述，数据表明妊娠第16至22天分离的卵黄囊产生的低密度脂蛋白亚类的密度取决于妊娠阶段。此外，在器官培养中添加不饱和或饱和脂肪酸对妊娠第18天卵黄囊分泌的脂蛋白的分泌速率和密度有不同影响。
