AJP - Cell Physiology, Vol 245, Issue 5 428-C438, Copyright © 1983 by American Physiological Society
Regional cerebral glucose utilization measured with [14C]glucose in brief experiments
D. M. Lu, D. W. Davis, A. M. Mans and R. A. Hawkins
A method was developed to measure regional cerebral glucose utilization
(rCMRGlc) in very short times using autoradiography and [2- 14C]glucose. It
includes a more comprehensive mathematical treatment than prototypes and
allows greater experimental flexibility. The current model takes into
account the exchange of glucose between plasma and brain as a function of
the plasma glucose concentration and rCMRGlc. The loss of 14C as 14CO2,
although relatively small, is also calculated and the results corrected
accordingly. Fully metabolizable radiolabeled glucose was chosen as the
tracer, because it most closely resembles the natural substrate. Glucose is
more rapidly phosphorylated than analogues such as 2-deoxyglucose and the
14C accumulated within intermediary metabolites soon account for most of
the radioactivity in cerebral tissue. Furthermore, no special constant is
necessary to adjust the rates as is the case when analogues are used.
Excellent anatomic resolution was achieved when the technique was used to
determine rCMRGlc in experiments as short as 5 min. By taking this
approach, more short-lived phenomena may be studied under more diverse
conditions than was previously possible.
