Ahmad P M, Russell T R, Ahmad F
Biochem J. 1979 Aug 15;182(2):509-14. doi: 10.1042/bj1820509.
3T3-L fibroblasts differentiate into adipose cells when maintained in a non-growing state. The specific activity of fatty acid synthetase of differentiated cells was 25--30-fold higher than that present in 3T3-L fibroblasts or in 3T3-C2 cells that possess an extremely low incidence of differentiation to adipocytes. The results of immunochemical analysis indicate that the increased specific activity of fatty acid synthetase in the differentiated cells is due to an increase in the cellular content of this enzyme. The rate of conversion of adipose cells was accelerated by brief exposure of confluent non-growing cultures of 3T3-L cells to 3-isobutyl-1-methylxanthine. This was accompanied by an increase in the specificity activity of fatty acid synthetase, which was also shown to be due to an increase in the cellular content of this enzyme. The continuous presence of 3-isobutyl-1-methylxanthine in the culture medium was not required to elicit the morphological and biochemical changes in 3T3-L cells that occurred many days after the removal of the inducer but earlier than the onset of spontanous differentiation.
3T3-L成纤维细胞在维持非生长状态时会分化为脂肪细胞。分化细胞中脂肪酸合成酶的比活性比3T3-L成纤维细胞或3T3-C2细胞（后者向脂肪细胞分化的发生率极低）中该酶的比活性高25至30倍。免疫化学分析结果表明，分化细胞中脂肪酸合成酶比活性的增加是由于该酶细胞含量的增加。通过将汇合的非生长状态的3T3-L细胞短暂暴露于3-异丁基-1-甲基黄嘌呤，脂肪细胞的转化速率加快。这伴随着脂肪酸合成酶比活性的增加，这也表明是由于该酶细胞含量的增加。在去除诱导剂许多天后但早于自发分化开始之前，3T3-L细胞发生形态和生化变化并不需要在培养基中持续存在3-异丁基-1-甲基黄嘌呤。
