Rosenthal M D, Geyer R P
Biochim Biophys Acta. 1976 Sep 27;441(3):465-76. doi: 10.1016/0005-2760(76)90243-5.
Human fibroblasts of both fetal and adult origin incorporated [1-14C] acetate primarily into phospholipid acyl groups (70-80% of total radioactivity). When these labeled cells were replated in non-radioactive medium, there was continuous loss of 14C from steroids, triacylglycerols and non-lipid material. In contrast, after some initial loss, cell lines of fetal origin completely retained 14C in cellular phospholipids during continued cell division. Unlike cells of fetal origin, fibroblasts of adult origin continued to lose radioactivity from their phospholipid acyl groups during growth in unlabeled medium. Loss of radioactivity from [1-3H] acetate incorporated into phospholipids of adult cells cannot be attributed to cell death since it was not accompanied by any loss of previously incorporated [ME-14C] thymidine. If cellular phospholipids were labeled with [U-14C] glycerol, both fetal and adult fibroblasts continued to lose radioisotope from the cells during growth in nonradioactive medium. Thus, there is turnover of the phospholipid molecules themselves in fetal human fibroblasts grown in vitro, but their acyl groups are retained within cellular phospholipids. In this respect, fibroblasts of fetal origin resemble established cell lines such as the L fibroblast. Fibroblasts of adult origin do not exhibit this complete conservation of their phospholipid acyl groups.
来自胎儿和成体的人成纤维细胞将[1-¹⁴C]乙酸盐主要掺入磷脂酰基（占总放射性的70-80%）。当这些标记细胞重新接种到无放射性培养基中时，类固醇、三酰甘油和非脂质物质中的¹⁴C持续损失。相比之下，经过一些初始损失后，胎儿来源的细胞系在持续细胞分裂过程中，细胞磷脂中完全保留了¹⁴C。与胎儿来源的细胞不同，成体来源的成纤维细胞在无标记培养基中生长时，其磷脂酰基继续损失放射性。掺入成体细胞磷脂中的[1-³H]乙酸盐的放射性损失不能归因于细胞死亡，因为这并未伴随着先前掺入的[甲基-¹⁴C]胸苷的任何损失。如果用[U-¹⁴C]甘油标记细胞磷脂，胎儿和成体成纤维细胞在无放射性培养基中生长时，细胞都会继续损失放射性同位素。因此，体外培养的胎儿人成纤维细胞中磷脂分子本身存在周转，但它们的酰基保留在细胞磷脂内。在这方面，胎儿来源的成纤维细胞类似于已建立的细胞系，如L成纤维细胞。成体来源的成纤维细胞在其磷脂酰基的这种完全保守性方面表现不同。
