The concentration and flux of adenine nucleotides and glycolytic intermediates were studied in brains of uremic rats and in rats infused with adenosine. Blood total adenine nucleotide levels were normal in uremic rats and raised in those infused with adenosine. Brain total adenine nucleotide levels were normal in both groups. In uremia and following adenosine infusion, brain levels of creatine phosphate (CP), adenosine triphosphate (ATP), and glucose increased, while creatine, adenosine diphosphate (ADP), adenosine monophosphate (AMP), and lactate decreased. Whole brain Na+ K+ adenosine triphosphatase (ATPase) was normal in uremic rats. Brain metabolic rate was reduced in uremic rats. It is suggested that uremia, like anesthesia, depresses brain utilization of ATP without detected inhibition of the capacity to produce ATP. Adenosine infusion, like sleep, permits normal utilization of ATP but enhances the potential for ATP synthesis.