de Alaniz M J, de Gómez Dumm I N
Istituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CONICET-UNLP Facultad de Ciencias Médicas, Argentina.
Mol Cell Biochem. 1990 Mar 5;93(1):77-85. doi: 10.1007/BF00223495.
The desaturation and chain elongation of [1-14C] alpha-linolenic acid were studied in HTC cells preincubated for 24 h in the presence of different unlabeled fatty acids of (n-3) and (n-6) series. After 24 h in the presence of [1-14C] alpha-18:3, cells transformed this acid into labeled 20:5 and 22:5(n-3) through the desaturation-elongation pathway and into 20:3 and 22:3(n-3) by the elongation reactions. The preincubation of HTC cells with (n-3) fatty acids (alpha-18:3, 20:5 and 22:6) produced an increase in the amount of [1-14C] alpha-18:3 that remained in the cells without being metabolized and consequently, a decrease in the last product formed, the 22:5(n-3) was observed. Simultaneously, the desaturation-elongation products decreased significantly and those of the elongation pathway were not modified, except when the cells were pre-incubated with the last fatty acid of this family (22:6) which increased this metabolic route. Fatty acids of (n-6) series (gamma-18:3, 20:3, 20:4 and 22:4) decreased the desaturation-elongation pathway and increased the elongation route from [1-14C] alpha-18:3. From these results, it can be concluded that fatty acids of (n-3) family and intermediates of (n-6) series would impair the [1-14C] alpha-18:3 metabolism at the delta 6 desaturation step. The fatty acid composition of the cells was also modified by the preincubation with (n-3) and (n-6) acids showing a decrease on delta 9 desaturation activity.
在存在不同的（n - 3）和（n - 6）系列未标记脂肪酸的情况下，对HTC细胞进行24小时预孵育，然后研究[1 - 14C]α-亚麻酸的去饱和及链延长过程。在[1 - 14C]α-18:3存在24小时后，细胞通过去饱和-延长途径将该酸转化为标记的20:5和22:5（n - 3），并通过延长反应将其转化为20:3和22:3（n - 3）。用（n - 3）脂肪酸（α-18:3、20:5和22:6）对HTC细胞进行预孵育，导致未被代谢而留在细胞中的[1 - 14C]α-18:3量增加，因此，观察到最终产物22:5（n - 3）的量减少。同时，去饱和-延长产物显著减少，而延长途径的产物未发生改变，除非细胞用该家族的最后一种脂肪酸（22:6）进行预孵育，此时该代谢途径会增加。（n - 6）系列脂肪酸（γ-18:3、20:3、20:4和22:4）减少了去饱和-延长途径，并增加了来自[1 - 14C]α-18:3的延长途径。从这些结果可以得出结论，（n - 3）家族脂肪酸和（n - 6）系列中间体在δ6去饱和步骤会损害[1 - 14C]α-18:3的代谢。用（n - 3）和（n - 6）酸进行预孵育也会改变细胞的脂肪酸组成，表现为δ9去饱和活性降低。
