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

The study investigates the use of three 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 facilitates the visualization of various structures within wool follicles and reveals the distribution of several dehydrogenases, such as succinic, α-glycerophosphoric, lactic, and malic, in frozen sections. The study highlights metabolic activity in the Malpighian layers and undifferentiated epidermal cells, where INT is enzymatically reduced, and notes the presence of protein-bound sulphydryl groups that produce distinct red staining. 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.