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The Interaction of Transport and Metabolism on Brain Glucose Utilization: A Reevaluation of the Lumped Constant
Author(s) -
Crane Paul D,
Pardridge William M,
Braun Leon D,
Nyerges Anthony M,
Oldendorf William H
Publication year - 1981
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.1471-4159.1981.tb00607.x
Subject(s) - constant (computer programming) , metabolism , carbohydrate metabolism , chemistry , medicine , endocrinology , neuroscience , biochemistry , biology , computer science , programming language
The relative cerebral cortical metabolism of glucose (GLU) and 2‐deoxy‐D‐glucose (DG) was measured in vivo in control and insulin‐treated hypoglycemic rats. The ratio of the utilization rate constants for the two hexoses, i.e., K DG / K CLU is defined as the Hexose Utilization Index (HUI). The HUI was found to be invariant in rats whose cerebral glucose content exceeded 1 μmo1.g −1 wet weight (HUI = 0.48 ± 0.07). Severe hypoglycemia (plasma glucose <2 mM) effected a shift in the HUI to 1.04 ± 0.21. The results are consistent with a model in which the interpretation of the HUI is determined by the rate of transport into brain, or subsequent phosphorylation, as the rate‐limiting step for hexose utilization.