AJP - Endocrinology and Metabolism, Vol 254, Issue 3 E310-E317, Copyright © 1988 by American Physiological Society
Comparison of [14C]glucose and [14C]deoxyglucose as tracers of brain glucose use
R. A. Hawkins, A. M. Mans, D. W. Davis and M. R. DeJoseph
Department of Anesthesia, Hershey Medical Center, Hershey, Pennsylvania 17033.
Because glucose metabolism and functional activity in brain regions are
normally coupled, knowledge of regional brain glucose use can yield
insights into regional functional activity. The deoxyglucose (DG) method is
widely used for this purpose in experimental animals and humans but
questions have arisen regarding its limits and accuracy. Therefore an
experiment was designed to compare the DG method on a
structure-by-structure basis with another tracer of glucose use,
[6-14C]glucose, in normal rats. The cerebral metabolic rates obtained using
the two tracers were similar in the telencephalon, but the results using DG
were substantially lower in the midbrain and hindbrain (diencephalon, 18%;
mesencephalon, 20%; metencephalon, 29%; and myelencephalon, 35%). The
primary DG metabolite, DG 6-phosphate (DG-6-P) was found to disappear in a
non-uniform manner from the major brain structures: telencephalon less than
diencephalon less than mesencephalon = metencephalon less than
myelencephalon. Thus a correlation was found between the rate of DG-6-P
loss and the extent to which the DG method gave lower values of glucose
use. Thus this may explain, at least in part, the discrepancies between the
two methods.
