Histochemical studies of some hydrolytic and oxidative enzymes in the skin epidermis of the clingfish Lepadogaster candollei Risso (Gobiesociformes, Pisces).

The skin epidermis of the Teleost fish Lepadogaster candollei has been studied by cytoenzymatic methods. Besides the common epithelial cells, the epidermis is constituted of various cell types, among which are calciform cells, sacciform cells and acidophilic cells. In the cells of the basal epithelium are found hydrolytic enzymes and oxidation-reduction enzyme systems that are tied to processes of growth and cell proliferation. The positive cytoenzymatic reactions in the epithelial elements and in the glandular sacciform cells of the intermediate layers reflect their high metabolic activity. There is even more intense activity in the polygonal epithelial cells of the more superficial layers whose enzymatic machinery is characterized by high reductase and oxidoreductase activities and by alkaline phosphatase activity. These results suggest an active utilization of glucose by anaerobic and aerobic processes as well as by the pentose phosphate shunt thus suggesting the absence of the keratinization processes in the piscine skin epidermis. The cytoenzymatic findings also demonstrate that the epidermis is capable of synthesizing and elaborating materials for cell regeneration.