Ketone Bodies as Precursors of Sterols and Fatty Acids in the Developing Rat

Four substances, β-hydroxy[3-14C]butyrate, [3-14C]acetoacetate, [2-14C]acetate and [2-14C]mevalonate, were compared by subcutaneous injection in 9- to 12-day-old rats as precursors of lipids in the central nervous system and in other organs. Subcutaneously injected mevalonate is a poor substrate for sterol synthesis in the central nervous system as compared to the utilization by the liver and kidneys, the latter taking far the largest share of available mevalonate for sterol biosynthesis. The data obtained demonstrated that 3-hydroxybutyrate was the preferred substrate for sterol and fatty acid biosynthesis in the three organs of ectodermal origin: the brain, spinal cord, and the skin. It is postulated that ketone bodies play a major role in the central nervous system during myelination not only as sources of energy, but also of carbon for lipid biosynthesis.