Histochemical patterns in the tadpole tail during normal and thyroxine-induced metamorphosis: I. Alkaline phosphatase, acid phosphatase, esterase, and aminopeptidase

Abstract

The distribution of alkaline phosphatase, acid phosphatase, esterase, and aminopeptidase was demonstrated by histochemical methods in sections of both growing and resorbing tails of Rana pipiens tadpoles. In general, main sites of localization of each of the enzymes were the epidermis and connective tissue, but not striated muscle. In addition, alkaline phosphatase, acid phosphatase, and esterase were present in the ependyma of the spinal cord and the endothelium of various blood vessels. The latter two enzymes were also found in spinal ganglia and, along with aminopeptidase, in the notochord. As the tail shortened during both normal and thyroxine-induced metamorphosis, activity of these enzymes increased; it became particularly prominent in the epidermis and in phagocytes in the connective tissue. These data on the differential distribution of four hydrolytic enzymes in the R. pipiens tail support histochemical and biochemical studies in other species.