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Role of Acetyl‐ l ‐Carnitine in Rat Brain Lipogenesis: Implications for Polyunsaturated Fatty Acid Biosynthesis
Author(s) -
Ricciolini Rita,
Scalibastri Maurizio,
Kelleher Joanne K.,
Carminati Paolo,
Calvani Menotti,
Arduini Arduino
Publication year - 1998
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 - 10.1046/j.1471-4159.1998.71062510.x
Subject(s) - lipogenesis , polyunsaturated fatty acid , carnitine , metabolism , chemistry , biochemistry , biosynthesis , fatty acid , medicine , endocrinology , lipid metabolism , biology , enzyme
This study was undertaken to explore the metabolic fate of acetyl‐ l ‐carnitine in rat brain. To measure the flux of carbon atoms into anabolic processes occurring at regional levels, we have injected [1‐ 14 C]acetyl‐ l ‐carnitine into the lateral brain ventricle of conscious rats. After injection of [1‐ 14 C]acetyl‐ l ‐carnitine, the majority of radioactivity was recovered as 14 CO 2 expired (60% of that injected). The percentage of radioactivity recovered in brain was 1.95, 1.60, 1.30, and 0.93% at 1, 3, 6, and 22 h, respectively. Radioactivity distribution in various lipid components indicated that the fatty acid moiety of phospholipid contained the majority of radioactivity. The radioactive profile of these fatty acids showed that the acetyl moiety of acetyl‐ l ‐carnitine was incorporated into saturated (60%), monounsaturated (15%), and polyunsaturated (25%) fatty acids [mainly present in 20:4 (5.2%) and 22:6 (7.8%)]. Injection in the brain ventricle of radioactive glucose, the major source of acetyl‐CoA in the CNS, revealed that glucose was a precursor of saturated (85%) and monounsaturated (15%) but not of polyunsaturated fatty acids. Thus, this study demonstrated distinct fates of glucose and acetyl‐ l ‐carnitine following intracerebroventricular injection. In summary, these data implicate acetyl‐ l ‐carnitine as an important member of a complex acetate trafficking system in brain lipid metabolism.