Inhibitory effect of added adenosine diphosphate on palmitate oxidation in mitochondria from rat brain

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5018711

Kawamura, N

It is generally accepted that fatty acids are poor substrates for the oxidation in brain because plasma fatty acids do not traverse the blood-brain barrier. However, a regional difference in the barrier suggests that fatty acids are available for oxidation. Why most of fatty acids are not oxidized is not certain. For this reason, regulation of oxidation of (1-/sup 14/C)palmitate (pal) in rat brain has been studied in nonsynaptic mitochondria (mit) prepared by use of Ficoll/sucrose density gradient. The authors found two contrasting oxidations with respect to ATP concentration; Type A at 2 mM and Type B at 0.5 mM. The rate of Type A was 50% of the level of B. Type A was inhibited by high levels of L-carnitine (car) and Mg/sup 2 +/. Added ADP inhibited Type A, but stimulated B. Addition of carboxyatractyloside was stimulatory for Type A, but inhibitory for B. The rate of Type A showed a downward curvature with increasing protein concentration while that of B showed a linear relationship. Addition of NH/sub 4//sup +/ to Type A stimulated the rate and reduced the inhibitory effects of both added ADP and high levels of car. These results suggest that under the normal level of ATP, the carnitine-dependent transport of pal is inhibited (thereby resulting in the inhibition in pal oxidation) by the transport of ADP into mit mediated by the ATP-ADP translocase, but that the inhibition is not observed under the specified conditions or regions where ATP levels are low or ammonia levels are high.

• Research Organization: Johns Hopkins Univ., Baltimore, MD
• OSTI ID: 5018711
• Report Number(s): CONF-8606151-; TRN: 86-034869
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ADP
BIOLOGICAL EFFECTS
HEXADECANOIC ACID
METABOLISM
ATP
BLOOD-BRAIN BARRIER
BRAIN
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARNITINE
MEMBRANE TRANSPORT
MITOCHONDRIA
RATS
TRACER TECHNIQUES
AMINO ACIDS
ANIMALS
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
HYDROXY ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MONOCARBOXYLIC ACIDS
NERVOUS SYSTEM
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
RODENTS
VERTEBRATES
VITAMIN B GROUP
VITAMINS
550501* - Metabolism- Tracer Techniques