Metabolites of 2-deoxyglucose in rat brain at 12-24 hr: Bounds on kinetic constants

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · American Journal of Physiology; (USA)

OSTI ID:7018823

Bass, L; Bodsch, W; Robinson, P J; Young, M O ^[1]

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1. Univ. of Queensland, St. Lucia (Australia) Univ. of California, Irvine (USA) Queensland Institute of Technology, Brisbane (Australia)

Activities of 2-deoxy-D-glucose and its metabolites in rat brain were examined at 12, 16, 20, and 24 h after intraperitoneal injection of {sup 14}C-labeled 2-deoxy-D-glucose. Plasma radioactivity was monitored for 2 h before each of these determinations. As proportion of total brain radioactivity, 2-deoxy-D-glucose decreased monotonically from the unexpectedly high value of 22% at 12 h to 11% at 24 h after injection, 2-deoxy-D-glucose 6-phosphate decreased monotonically from 69% at 12 h to 23% at 24 h, and unphosphorylated products (of high and low molecular weight) increased from 10% at 12 h to 64% at 24 h. The data were analyzed in terms of a four-compartment model. Secure lower and upper bounds on the rate constant, k{sup *}{sub 4}, for the dephosphorylation of 2-deoxy-D-glucose 6-phosphate were established: k{sup *}{sub 4} was at least 0.0158 {plus minus} 0.0014{center dot}min{sup {minus}1} and at most 0.0385 {plus minus} 0.0037{center dot}min{sup {minus}1}. If k{sup *}{sub 4} is constant in time, then appreciable dephosphorylation occurs within the 45-min experimental period commonly used in the standard 2-deoxy-D-glucose method for estimating local cerebral glucose utilization. The possibility that the effective k{sup *}{sub 4} is lower at such early times is reviewed in the light of a reanalysis of previously published data. Implications of these results for the 2-deoxy-D-glucose method are discussed from the points of view of numerical analysis and capillary heterogeneity.

• OSTI ID: 7018823
• Journal Information: American Journal of Physiology; (USA), Vol. 253:4; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BRAIN
METABOLISM
CARBON 14 COMPOUNDS
BIOCHEMICAL REACTION KINETICS
GLUCOSE
COMPARTMENTS
ION EXCHANGE CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
PHOSPHATASES
PHOSPHORYLATION
RATS
THIN-LAYER CHROMATOGRAPHY
ALDEHYDES
ANIMALS
BODY
CARBOHYDRATES
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
CHROMATOGRAPHY
ENZYMES
ESTERASES
HEXOSES
HYDROLASES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MONOSACCHARIDES
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques