Suzuki F, Kato K
Biochim Biophys Acta. 1986 Oct 31;889(1):84-90. doi: 10.1016/0167-4889(86)90011-x.
The mechanism of S-100 protein release from adipocytes, which is apparently coupled with lipolytic activity, was investigated in vitro using rat epididymal fat pads. The S-100 protein release was increased severalfold by 10 microM epinephrine in the medium containing a low concentration (less than 5 mg/ml) of albumin, but the release was enhanced only slightly when the medium contained a high concentration (more than 20 mg/ml) of albumin. On the other hand, the maximum rate of free fatty acid release measured simultaneously was observed in medium containing more than 20 mg/ml albumin. The rate of S-100 protein release was found to be closely related to the concentrations of both albumin added to the incubation medium and fatty acids released into it, and the rate was increased under conditions wherein the molar ratio of fatty acid/albumin was greater than 6. The S-100 protein release from fat pads was also enhanced solely by the addition of an excess amount (6 mM) of palmitic acid or oleic acid. The basal release of S-100 protein at a high concentration of albumin in the fat pads of diabetic or long-term starved rats, in which the fatty acid level in adipocytes is known to be enhanced, was about 7- and 2-fold higher, respectively, than that of control fed rats. These results suggest that S-100 protein in adipocytes is released under conditions in which the fatty acids being produced are not released promptly and are accumulated in the cells.
利用大鼠附睾脂肪垫在体外研究了脂肪细胞释放S - 100蛋白的机制，该机制显然与脂解活性相关。在含有低浓度（低于5mg/ml）白蛋白的培养基中，10μM肾上腺素可使S - 100蛋白释放增加数倍，但当培养基中含有高浓度（超过20mg/ml）白蛋白时，释放仅略有增强。另一方面，同时测量的游离脂肪酸最大释放速率在含有超过20mg/ml白蛋白的培养基中观察到。发现S - 100蛋白释放速率与添加到孵育培养基中的白蛋白浓度以及释放到其中的脂肪酸浓度密切相关，并且在脂肪酸/白蛋白摩尔比大于6的条件下释放速率增加。仅通过添加过量（6mM）的棕榈酸或油酸也可增强脂肪垫中S - 100蛋白的释放。在糖尿病或长期饥饿大鼠的脂肪垫中，已知脂肪细胞中的脂肪酸水平会升高，在高浓度白蛋白条件下，S - 100蛋白的基础释放分别比对照喂养大鼠高约7倍和2倍。这些结果表明，脂肪细胞中的S - 100蛋白是在产生的脂肪酸未及时释放并在细胞中积累的条件下释放的。
