Alternative pathways of carbohydrate metabolism in foetal and adult tissues.

and plasmalogen compounds and sphingomyelin was computed from the analysis of the fractions. 3. Choline plasmalogen was present in similar proportions in the whole muscle and myofibrils of rabbit muscle, but was virtually absent from trout muscle. 4. The constituent fatty acids and aldehydes from the separated phospholipids and some triglyceride fractions were identified and estimated by gas chromatography. 5. In general the results showed a preponderance of C15 saturated acids or aldehydes, and of polyenoic acids, in the kephalins, and of the C01 saturated compounds in phosphatidylcholine and choline plasmalogen, with the exception of liver and trout-muscle lecithins, which contained large amounts of C. acids. 6. The fatty aldehydes fall in a narrower range (C14-C18) than the fatty acids (C14-C2), and included both unsaturated and branched-chain aldehydes, which varied considerably in proportion in different species. 7. The different fatty acid composition of lecithin, kephalin and triglyceride components of various tissues should be considered in possible routes of biosynthesis.