Simultaneous Measurement of Local Glucose Utilization and Blood Flow in the Rat Brain: An Autoradiographic Method Using Two Tracers Labeled with Carbon-14

A simplified technique that uses two radionuclide tracers has been devised to measure local cerebral glucose utilization (lCGU) and local cerebral blood flow (lCBF) in the same rat. The method employs [¹⁴C]-2-deoxyglucose and [¹⁴C]iodoantipyrine to produce an autoradiogram before and another after extraction into chloroform of the [¹⁴C]iodoantipyrine from the brain sections. The chloroform-extracted autoradiogram yields lCGU, and the difference in tissue carbon-14 concentration between the two autoradiograms permits calculation of lCBF. The double-isotope technique provides values of lCGU and lCBF that are statistically indistinguishable from those derived from conventional single-isotope methods.