Zhou Q, Kummerow F A
Burnsides Research Laboratory, University of Illinois, Urbana 61801, USA.
Biomed Environ Sci. 1997 Dec;10(4):369-76.
The relationships among sphingomyelin synthesis cytosolic free Ca++ level and cytotoxicity in the presence of 27-hydroxycholesterol were investigated by measurement of [methyl-3H] choline incorporation into sphingomyelin, phosphatidylcholine, phosphocholine and cytidine choline 5'-diphosphate, 45Ca++ uptake, cytosolic free Ca++ levels and viable cell numbers. The results indicated that 27-hydroxycholesterol at higher than normal level induced increased [3H] choline incorporation in sphingomyelin accompanied by decreased radioactivity in phosphatidylcholine but did not alter [3H] choline content in phosphocholine and cytidine choline 5'-diphosphate. The increased radioactivity in sphingomyelin by 27-hydroxycholesterol was detected first, followed by detection of the enhanced Ca++ uptake and cytosolic free Ca++. Finally, a decrease in viable cell number occurred. We suggest that the increased transfer from phosphatidylcholine to sphingomyelin by 27-hydroxycholesterol may be related to enhanced cytosolic free Ca++.
通过测量[甲基-3H]胆碱掺入鞘磷脂、磷脂酰胆碱、磷酸胆碱和胞苷胆碱5'-二磷酸的量、45Ca++摄取量、胞质游离Ca++水平和活细胞数量，研究了27-羟基胆固醇存在下鞘磷脂合成、胞质游离Ca++水平与细胞毒性之间的关系。结果表明，高于正常水平的27-羟基胆固醇诱导鞘磷脂中[3H]胆碱掺入增加，同时磷脂酰胆碱中的放射性降低，但不改变磷酸胆碱和胞苷胆碱5'-二磷酸中[3H]胆碱的含量。27-羟基胆固醇首先检测到鞘磷脂中放射性增加，随后检测到Ca++摄取增强和胞质游离Ca++增加。最后，活细胞数量减少。我们认为，27-羟基胆固醇使从磷脂酰胆碱到鞘磷脂的转移增加可能与胞质游离Ca++增加有关。
