The Localization of Dehydrogenase Activity and Sulfhydryl Groups in Wool and Hair Follicles Using Tetrazolium Salts

The study investigates the use of tetrazolium salts as indicators of dehydrogenase activity in the skin of sheep and other mammals, with 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl-tetrazolium chloride (INT) identified as the most effective. INT allows for the visualization of various histological structures in wool follicles and reveals the distribution of several dehydrogenases and phosphorylated carbohydrate intermediates. Metabolic activity is observed in the Malpighian layers and undifferentiated epidermal cells, with intense red staining indicating protein-bound sulphydryl groups. The distribution of cytochrome oxidase is similar to that of dehydrogenase activity, and INT is also used to estimate succinic dehydrogenase in skin and kidney tissues.