Lipogenesis in the developing brain from intracranially administered [1‐¹⁴C] acetate and [U‐¹⁴C] glucose

Fifteen‐day‐old rats divided into two groups were given [1‐ 14 C]acetate or [U‐ 14 C] glucose by intracranial injection and were sacrificed after 1 hr. Analysis of lipids from the two groups showed differences in the incorporation of radioactivity in the polar lipids and cholesterol. Analysis of brain fatty acid showed that whereas radioactivity from acetate was incorporated into saturated, monoand polyunsaturated fatty acids, the radioactivity from [U‐ 14 C] glucose was found only in 16∶0, 18∶0, and 18∶1. No radioactivity was found in polyunsaturated fatty acids even after concentration of this fraction by AgNO 3 :SiO 2 thin layer chromatographic method. This difference is discussed in hypothetical terms of nonhomogeneous acetyl CoA pool, formation of acetyl CoA from glucose exclusively inside the mitochondria, and activation of injected acetate to acetyl CoA.