Abstract
Summary
Essential fatty acid-deficient rats were subjected to fasting-refeeding or partial hepatectomy to stimulate liver phos-pholipid and membrane formation under conditions of limited essential fatty acid (EFA) supply. Refeeding after fasting decreased the proportion of arachidonate in liver phospholipid fatty acids only slightly, i.e., from 6.8% in nonfasted rats to 5.3% after 3 or 7 days of refeeding, whereas ei-cosatrienoate decreased from 19.8% in nonfasted rats to 13.0% after 3 days of refeeding, with a return to nonfasted levels after 7 days. Activities of liver glucose-6-phosphate dehydrogenase and fatty acid synthetase in fasted-refed EFA-deficient rats did not differ significantly from values in deficient rats fed ad libitum. Considerable increase in liver weight (ca. 3-8 g or at least 50% of the estimated preoperative weight) occurred after partial hepatectomy of EFA-deficient rats. The proportion of arachidon-ate in phospholipid fatty acids was slightly lower after hepatectomy than before.
These results indicate that: (a) little of the arachidonate in EFA-depleted liver is used for lipoprotein formation and transport after fasting-refeeding, whereas eicosatri-enoate is available; (b) fasting-refeeding of EFA-deficient rats does not increase activities of liver glucose-6-phosphate dehydrogenase and fatty acid synthetase above the already elevated levels in EFA-deficient rats fed ad libitum; (c) considerable new liver tissue can be formed after partial hepatectomy even when EFA levels in phospholip-ids are very low.
Supported in part by USPHS Grant No. AM 12024.
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