Uptake of cerebroside, cholesterol and lecithin by brain myelin and mitochondria.

The uptake of emulsified labeled lipids by rat brain myelin and mitochondria was studied. Cerebroside and lecithin uptakes were greatly stimulated by addition of salts, particularly those containing divalent cations. Cholesterol uptake was not influenced by salts. Increasing concentrations of detergent (non-ionic) were inhibitory. Delipidated membranes took up much less lipid, but pretreatment with lecithin partially restored the ability to take up cerebroside and cholesterol. The lipid uptake appears to be nonenzymatic and appears to depend on the size of the emulsified particles. The possible role of such a phenomenon in membrane formation and maintenance is discussed.