[Early modification of the fatty acid composition of cardiolipins and other phospholipids in rat liver mitochondria during dietary deficiency of essential fatty acids followed by repletion].

Weaned rats (21-day old, 44 +/- 2 g) were distributed into 3 groups. The first group was raised on a laboratory diet for 7 or 20 days (control group). The second was fed a diet containing 0.07% fat for 1, 2, 3, 7 or 66 days. The third one was fed the low-fat diet for 7 days and then switched to a laboratory chow diet for 1, 2, 5 or 9 days. Cardiolipin (CL) on the one hand and other mitochondrial phospholipids taken as a whole (PLm) on the other hand were prepared from liver mitochondria and their fatty acids analysed. Polyunsaturated fatty acids in PLm (18:2 (n-6), 20:4 (n-6), 22:6 (n-3) acids) decreased abruptly during the first 3 days of fat deficiency and then remained rather stable till day 7. CL behaved in a quite different way. 18:2 (n-6) acid, the major polyunsaturated fatty acid of CL, decreased continuously between day 1 and day 7 from 79% to 33%. A value of 19.6% was reached on day 66. When deficient rats were transferred to an equilibrated diet, the fatty acid profile of PLm was rapidly restored. Major effects were already achieved during the first 24 h and a fatty acid composition identical to that of control rats was reached within 2 days. A considerably longer period (about 9 days) was necessary for CL to reach a level analogous to that of control rats. The diminution of linoleic acid in CL was brought about by increases in the levels of monoenoic acids: palmitoleic (16:1 (n-7)), oleic (18:1 (n-9)) and cis-vaccenic (18:1 (n-7)) acids which accounted for 18.0%, 17.7% and 17.9% respectively on day 7. Increases in the (n-7) monoenes remained comparatively low in PLm, which showed a sharp rise in their oleic acid content (from 3.9% to 12.7% in 3 days). The proportion of cis-vaccenic acid relative to total octadecenoic acids was decreased from 75% to 50% in CL. A similar trend, but of smaller magnitude, was also noticed in PLm.(ABSTRACT TRUNCATED AT 400 WORDS)