Histochemical Study on the Differentiation of Metanephros in Albino Rats

Park, Kyung Seek; Kim, Dong Han

Abstract

Development and differentiation of mammalian kidney has been studied by many investigators. Hitreto, it has been known that a high vertebrate`s kidney was differentiated from as a metanephros. As a result of the study of most investigators on developmental processes of metanephros in man and rodents, they insisted that morphological development and differentiation of nephrons and collecting ducts should occur in the latter one quarter period of the fetal ages. But the initiation and completion time of renal function following its morphological development and differentiation have not been investigated perfectly. The author has determined the relationships of morphological and functional development of kidney were able to be revealed the studies of hydrolyzing phosphatase activities on the developing renal tissues. Therefore, in order to investigate the phosphatase activities of renal tissue following the development and differentiation of rate kidney, after interbreeding of healthy rats, fetuses of the 15th, 17th, 19th and newborns of the 1st, 4th, 7th and 10th day were sacrificed and were resected renal tissues. Histological preparations were prepared by way of hematoxylin and eosin stain for morphological changes of rat renal tissues, and Gomori's method(1941) for the detection of the activities of alkaline phosphatase, Gomori's method(1939) for the detection of the activities of acid phosphatase and Wachstein and Meisel's method(1957) for the detection of activities of ATPase were used, respectively. All of the preparations were observed with light microscope. The results were as follows; 1. The early differentiation of rat kidney began with glomerulus formation at the 17th day of fetal age and morphological development was completed at the 21th day of fetal age, and lobulation of kidney was observed at the 7th day of neonatal age. 2. In the fetal kidney of the 17th day, alkaline phosphatase activities were observed initially in the proximal tubules surrounding glomeruli in the cortico-medullary Junction, and the activities were increased at the 17th day of fetus. At the 21th day of fetus, the strength of the enzyme activity was increased at the same time as renal tubule which showed alkaline phosphatase activity was increased in the cortex. In the each newborn kidney, the enzyme activities were continuously increased in the proximal tubules at the 1st, 4th, 7th and 10th day of newborns. The renal corpuscle and ascending straight tubule of the Henle's loop showed trace activities. 3. Acid phosphatase activity was shown at renal tubules and glomeruli during the fetal age after the 17th day of fetus, and moderate reaction of the enzyme was shown in the renal tubules, glomeruli, medullary rays and Henle's loops after birth. 4. Adenosine triphosphatase showed moderate reaction in the glomerulus at the 17th day and 19th day of fetus, and strong reaction was shown at the 21th day of fetus, and the ATPase activities of medullary rays showed trace reaction after birth. According to the beginning and change of the enzyme activity as mentioned above, it was supposed that the development of rat kidney should begin at the 17th day of fetus. In the 21th day of fetus, diuresis and resorption were accomplished mostly in the glomerulus and proximal tubule, and resorpt. ion of the Henle's loop began just before and after the birth.