Activities and distribution of alkaline phosphatase and carbonic anhydrase in the tibial dyschondroplastic lesion and associated growth plate of chicks.

The tibial dyschondroplastic lesion and associated growth plate were examined for the presence of alkaline phosphatase, an enzyme important in cartilage mineralization, and carbonic anhydrase, an enzyme that regulates acid-base balance of many tissues including cartilage. By histochemistry, both enzymes were found to be present in the prehypertrophic and hypertrophic zones of the growth plate as occurs normally. Enzyme activity was normal or close to normal in the growth plate. Activity was diminished to half of the normal values in the proximal lesion and to zero in the distal lesion. The enzymes are believed to be diminished by necrotic and autolytic processes and are not involved in initiating the formation of the lesion.