Transport of 3-hydroxy(3-/sup 14/C)butyrate by dissociated cells from rat brain

Journal Article · Mon Aug 01 04:00:00 EDT 1988 · Am. J. Physiol.; (United States)

OSTI ID:6801664

Tildon, J T; Roeder, L M

Recent studies suggest that the utilization of oxidizable substrates by the brain may be regulated in part by transport across the plasma membrane. Dissociated brain cells obtained by mechanical disruption of rat brain were used to measure the uptake of 3-hydroxy(3-14C)butyrate. Total uptake revealed two mechanisms (diffusion and a carrier-mediated system). A Lineweaver-Burk plot of the latter component yielded an apparent Km of 1.47 mM and a maximal velocity (Vmax) of 5 nmol.min-1.mg protein-1. The rates of uptake were temperature dependent and were significantly higher at pH 6.2 than at pH 7.4 or 8.2. Preloading the cells and increasing the intracellular concentration of 3-hydroxybutyrate using 12.5 and 25 mM increased the rate of uptake 143 and 206%, respectively, indicative of an accelerative exchange mechanism. Uptake was inhibited approximately 50% by (in mM) 10 phenylpyruvate, 10 alpha-ketoisocaproate, 10 KCN, and 1.5 NaAsO/sub 2/. Uptake was also decreased by (in mM) 5 lactate, 5 methyl malonic acid, 1 alpha-cyano-4-hydroxycinnamate, and 1 mersalyl. Dissociated brain cells from 14- to 16-day-old rats accumulated 3-hydroxybutyrate at a rate more than two-fold greater than cells from either younger (2-day-old) or older (28-day-old and adult) animals. These data are consistent with the proposal that 3-hydroxybutyrate is taken up by the brain by both diffusion and a carrier-mediated transport system, and they support the hypothesis that transport at the cellular level contributes to the regulation of substrate utilization by the brain.

• Research Organization: Univ. of Maryland School of Medicine, Baltimore (USA)
• OSTI ID: 6801664
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 255; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BODY
BRAIN
BUTYRIC ACID
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
IN VITRO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
MONOCARBOXYLIC ACIDS
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RATS
RODENTS
TEMPERATURE DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES