ABSTRACT
Growth alters the ability of rat brain to incorporate [2-3H]glycerol into glycerides; indeed, 12 min after the intracranial administration of the precursor, diglyceride becomes more radioactive in newborn than in 19-day-old brain, the reverse being true for total glycerophospholipid and triglyceride. The ratio between the labeling of phospholipid and that of neutral lipid in the experimental conditions described in this paper is proposed as a marker of brain maturity. The distribution of labeling among phospholipid classes also varies with age, and the increase of labeling in total phospholipid occurring with increasing age is almost entirely due to phosphatidylethanolamine and phosphatidylcholine. The metabolism of myelin lipids might be responsible for these age-dependent variations. The administration of ethanol to dams during pregnancy and lactation alters the distribution of the label among neutral glycerolipid and total glycerophospholipid in an age-dependent manner. The labeling distribution among phospholipid classes is also affected.
Subject(s)
Aging/metabolism , Brain/metabolism , Ethanol/administration & dosage , Glycerides/metabolism , Glycerol/metabolism , Phospholipids/metabolism , Prenatal Exposure Delayed Effects , Animals , Brain/drug effects , Brain/growth & development , Female , Pregnancy , RatsABSTRACT
The incorporation of labeled glycerol into glycerolipid of rat brain was influenced by the age of the animal (2-month-old vs. newborn); indeed, 12 min after the administration, diglyceride was the most heavily labeled glycerolipid in the newborn brain, whereas the labeling of glycerophospholipid was highest in the adult. Various amounts of ethanol (0% to 36% of total energy intake) were administered to pregnant female rats, and the brains of their pups were examined for the ability to incorporate labeled glycerol into glycerolipid. The radioactivity incorporated into lipid diminished with increasing the amounts of alcohol consumed. The labeling pattern of lipid classes was also influenced; indeed, the radioactivity of diglyceride decreased markedly, whereas that of triglyceride and glycerophospholipid was affected to a lower degree. The distribution of radioactivity among different phospholipids also varied with age; on a percent basis, phosphatidylcholine was labeled less and phosphatidylinositol was labeled more in the newborn than in the adult. Ethanol influenced the pattern of glycerophospholipid labeling, increasing the radioactivity of phosphatidylserine and decreasing that of phosphatidylinositol.
Subject(s)
Brain/metabolism , Fetal Alcohol Spectrum Disorders/metabolism , Glycerol/metabolism , Lipids/biosynthesis , Age Factors , Animals , Animals, Newborn , Female , Phospholipids/biosynthesis , Pregnancy , Rats , Rats, Inbred StrainsABSTRACT
The ability of phosphorylcholine and CDP-choline to act as lipid precursors was tested in chick brain microsomes (plus supernatant). CDP-choline was, in every case, a much better precursor of choline glycerophospholipids than phosphorylcholine. The cytidylyltransferase reaction which forms CDP-choline appears, therefore, as the limiting step of the metabolic pathway which introduces phosphorylcholine into lipids. This reaction can be stimulated by the addition of phospholipids to the incubation mixture. Choline lysoglycerophospholipids are the most active in this connection.
