Incorporation of stearic acid into brain lipids in the developing brain: blood-brain relationships during development.

The blood-brain relationship for stearic acid varies during development. Subcutaneously injected [1-14C]-stearic acid is taken up by brain. Age-related changes in the metabolism of stearic acid have been determined in mouse brain from birth to maturity. Total lipid radioactivity reaches a maximum at 18 days of age and decreases afterwards until adulthood. However, specific radioactivity presents the highest value at 1 day of age and declines from then on. At any age, the injected acid is taken up and partly metabolized in the brain, either by elongation or by degradation in situ and resynthesis of new fatty acids; it is also desaturated, and the oleic acid thus formed is eventually elongated. The labeled stearic acid is incorporated into brain lipids with a different pattern according to the age of the injected animal.