Repetitive seizures were induced electrically in 109 male CFN rats that were paralyzed and ventilated with oxygen. Compared with the results in paralyzed, oxygen-ventilated controls receiving sham shocks, incorporation of radioactive leucine into cerebral proteins was decreased up to twofold in the cerebral hemispheres, cerebellum, and brain stem of the experimental animals. The extent of inhibition increased with the duration of seizures. The size of the leucine and protein pools was unaffected by seizures, but the specific activity of the cerebral leucine pool was 61 to 64 percent greater in experimental animals. The findings provide a potential explanation of some of the complications that often follow sustained cerebral paroxysmal activity even in the absence of convulsions.