Miller M, Motevalli M, Westphal D, Kwiterovich P O
Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Lipids. 1993 Jan;28(1):1-5. doi: 10.1007/BF02536351.
Confluent skin fibroblasts from normal humans were incubated in serum free medium with up to 100 nmole/mL eicosapentaenoic acid (EPA; bound to albumin in a 4.6:1 ratio) and compared with cells incubated with oleic acid (OA) at similar concentrations. The rate of [14C]OA incorporation into triacylglycerol (TG) (nmol/mg/h) was approximately 5-fold greater than that of [14C]EPA. The mass of TG formed after incubation of fibroblasts with EPA was also significantly lower than that formed with OA (43.2 +/- 9.3 vs. 59.5 +/- 6.6 micrograms/mg cell protein, respectively, P = 0.006). The addition of excess, unlabeled EPA reduced the rate of incorporation of [14C]OA into TG whereas unlabeled OA stimulated incorporation of [14C]EPA into TG. When the cells were preincubated with human serum basic proteins (BP I, II and III), the mass of TG formed (compared to baseline) was significantly higher with the basic proteins whether OA or EPA was studied. Only BP I significantly stimulated the mass of cell phospholipids, an effect that occurred with either OA or EPA in the medium. The results suggest that in cultured normal human fibroblasts, OA is a better substrate for TG synthesis than EPA and that this effect may be accentuated by the presence of the basis proteins.
将来自正常人的融合皮肤成纤维细胞在无血清培养基中与浓度高达100纳摩尔/毫升的二十碳五烯酸（EPA；与白蛋白以4.6:1的比例结合）一起孵育，并与在相似浓度下与油酸（OA）一起孵育的细胞进行比较。[14C]OA掺入三酰甘油（TG）的速率（纳摩尔/毫克/小时）比[14C]EPA的掺入速率大约高5倍。用EPA孵育成纤维细胞后形成的TG质量也明显低于用OA形成的TG质量（分别为43.2±9.3与59.5±6.6微克/毫克细胞蛋白，P = 0.006）。添加过量的未标记EPA会降低[14C]OA掺入TG的速率，而未标记的OA会刺激[14C]EPA掺入TG。当细胞与人血清碱性蛋白（BP I、II和III）预孵育时，无论研究的是OA还是EPA，碱性蛋白存在时形成的TG质量（与基线相比）都显著更高。只有BP I显著刺激细胞磷脂的质量，这种效应在培养基中存在OA或EPA时都会出现。结果表明，在培养的正常人成纤维细胞中，OA是比EPA更好的TG合成底物，并且碱性蛋白的存在可能会加剧这种效应。
