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Utilization of High‐Density Lipoprotein Sphingomyelin by the Developing and Mature Brain in the Rat
Author(s) -
Bentejac Marc,
Bugaut Maurice,
Delachambre Marie Claire,
Lecerf Jean
Publication year - 1989
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1989.tb09199.x
Subject(s) - sphingomyelin , phosphatidylcholine , lysophosphatidylcholine , choline , biochemistry , chemistry , lipoprotein , phospholipid , cholesterol , membrane
Utilization of very long chain saturated fatty acids by brain was studied by injecting 20‐day‐old and adult rats with high‐density lipoprotein containing [ stearic or lignoceric acid ‐ 14 C, (methyl‐ 3 H)choline]sphingomyelin. Labeling was followed for 24 h. Very small amounts of 14 C were recovered in the brain of all rats, and there was no preferential uptake of lignoceric acid. Approximately 20% of the entrapped 14 C was located in the form of unchanged sphingomyelin 24 h after injection. This result shows that the rat brain utilizes very little very long chain fatty acids (≥20 C atoms) from high‐density lipoprotein sphingomyelin, even during the myelinating period. The [ 3 H]choline moiety from sphingomyelin was recovered in brain phosphatidylcholine in a higher proportion in comparison with the 14 C uptake. The brain 3 H increased throughout the studied period in all experiments, but was much higher in the myelinating brain than in the mature brain. From the radioactivity distribution in liver and plasma lipids, it is clear that the choline 3 H in the brain originates from either double‐labeled phosphatidylcholine of lipoproteins or tritiated lysophosphatidylcholine bound to albumin, both synthesized by the liver.