Brain isoenzyme of creatine kinase. III. Active and inactive forms in dystrophic muscle of vitamin E-dificient rabbit.

Rabbits were fed a vitamin E-deficient diet for 7 weeks. Control rabbits, paired for weight, were pair-fed an identical diet supplemented with vitamin E. After 3 weeks the expermental animals showed a rise in serum creatin kinase activity which was attributable to the muscle isoenzyme (MM). No rise in creatine kinase activity or appearance of MM was noted in the serum of the control rabbits. Total creatine kinase activity and MM activity were reduced in the gastrocnemii of the experimental animals while the activities of the brain (BB) and hybird (MB) isoenzymes were increased. The specific activity of BB based on immunochemically determined BB protein was not different from normal in either the experimental or control group. Activation of pre-existing inactive BB is probably not the explanation for increased BB activity in the gastroncnemii of the experimental group.