[Proteolytic processes in rat brain and liver during adaptation to cold].

The autolysis and the neutral proteinase activity with respect to protamine in the brain and liver of rats were studied during cold adaptation, on the 1st, 3rd, 7th, 15th, and 45th days in the cold chamber at 2--4 degrees C. A short cold effect (1--3 days) decreases the brain autolysis by 33%, the liver one by 18%. The activity of protamine-lytic peptide-hydrolase diminishes nearly by half both in the brain and in the liver. In cold-adapted rats (45 days) the autolysis increases by 50% in the brain and by 24% in the liver. The activity of neutral peptide-hydrolase remains lowered by 43% in the brain and by 36% in the liver. Thus, only autolytic processes are intensified in cold-adapted animals while the neutral peptide-hydrolase does not participate in the increasing protein catabolism in the brain and liver.