Development of peroxisomes in amphibians. I. Cytochemical and biochemical studies on the small intestine

Abstract

Abstract The ontogeny of intestinal microperoxisomes was studied by cytochemical and biochemical methods during the development of two anuran amphibian species ( Rana catesbeiana and Alytes obstetricans ). The catalase activity was localized after incubation in DAB medium and studied biochemically by a spectrophotometric method. Microperoxisomes were found to be present in the intestinal epithelial cells of these amphibians. The primary enterocytes of aquatic larvae showed very few microperoxisomes. After metamorphosis the absorptive cells of the new secondary epithelium exhibited a drastically increased number of microperoxisomes per cell section. These organelles showed circular profiles and had a diameter ranging from 0.36 to 0.40 μm. The intestinal catalase activity was low in the tadpoles, increased steadily after metamorphosis, and peaked in the adults. Moreover, at eath developmental stage, the proximal segments always exhibited the highest catalase activity. The present study shows that the number of microperoxisomes as well as the catalase activity increases with the maturation of the intestinal epithelial cells in developing anuran amphibians.