Acetoacetate is a cholesterogenic precursor for myelinating rat brain and spinal cord Incorporation of label from [3-14C]acetoacetate, [14C]glucose and 3H2O

Abstract

Rat pups, 3 weeks old, were injected i.p. with combinations of ³H₂0 and either (3-¹⁴C]acetoacetate or [¹⁴C]glucose. ³H/¹⁴C incorporation ratios were measured in lipid fractions of homogenates and myelin prepared from whole brain and spinal cord. Spinal cord synthesized at least twice as much fatty acids and 3-fold more sterols than whole brain. Both tissues used acetoacetate preferentially for sterol synthesis, whereas label from [¹⁴C]glucose was distributed between fatty acids and sterols in the same way as ³H from

³H₂O. The relative contributions of acetoacetate to sterol synthesis in whole tissue and in the purified myelin fraction were about the same, both for the cerebrum and for the spinal cord.