Abstract: | Alkaline phosphatases have been demonstrated enzymhistochemically in the testis of the common frog Rana temporaria, caught in the month of January. The follicle cells in the cyst walls and the lamina propria of the seminiferous tubules showed strong enzymatic activity; also a weak activity was observed in the peripheral region of some of the germinal cells lying within the cysts. The possible interaction of alkaline phosphatases in the transport processes across the cyst walls has been discussed. |