A difference in the in vivo cerebral production of [1-14C] lactate from D-[3-14C] glucose in chronic mental patients.

Data from a study in which 12 chronic mental patients and 12 control subject were given D-[3-14C] glucose intravenously in our arterio-venous technique for determining cerebral metabolism in vivo were reexamined. Previously unpublished whole-blood lactate determinations in these experiments indicated a cerebral production of much higher specific activity of [1-14C]-lactate from the D-[3-14C] glucose by mental patients. Of several possible explanations offered for this difference, the most likely was that involving a small lactate compartment(s) in some specific region(s) in which decarboxylation of the endogenously formed cerebral lactate was partially inhibited. Two other experiments with mental patients (one given [U-14C] glucose and the other, [1-14C] glucose) whose extraordinary results were described, in part, in a previous report, were interpreted as more extreme examples of the production of higher specific activity 14C-lactate from 14C-glucose by mental patients' brains upon their very unusual whole blood lactate data.