Conversion of[U-14C]glucose into carbon dioxide, glycogen, cholesterol and fatty acids in liver slices from embryonic and growing chicks.

Incorporation of [U-(14)C]glucose into carbon dioxide, glycogen, cholesterol and fatty acids and of (3)H(2)O into cholesterol and fatty acids was measured in liver slices from embryos and growing chicks. During the embryonic period, rates of incorporation were low and stable for all pathways. Fatty acid synthesis and glucose oxidation increased promptly when the chicks were fed, reaching plateau levels within 6 days. Cholesterol and glycogen synthesis increased only slightly when the birds were fed. After 5 and 11 days respectively, cholesterol and glycogen synthesis began to increase rapidly. The rate of glucose oxidation in liver slices from 4-week-old chicks was 20-fold greater than in slices of embryonic liver; glycogen, cholesterol and fatty acid synthesis had increased approximately 100-, 300- and 1000-fold respectively. The increase in the metabolism of [U-(14)C]glucose that occurred after hatching was probably due to the change from a high-fat non-carbohydrate diet (yolk) to a high-carbohydrate low-fat diet (mash).