Abstract
Using the substrate film method of DAOUST (1957), the DNAase activity in the mesenteric lymph nodes, thymus, spleen, bone marrow and lung of normal male Wistar rats, weighing about 200g, has been studied, in comparsion with the degree of activity of this enzyme in the liver.
In the mesenteric lymph nodes and the thymus, there is a very low activity of DNAase in both the cortex and the medulla; and contrary to expectation, no higher activity was demonstrated in the pale-staining centers of the secondary nodules, which are considered to be the main sites of production and destruction of lymphocytes. Also, almost no activity was found in the white pulp of the spleen; whereas the splenic red pulp, particularly the BILLROTH's cords, definitely showed a high activity of DNAase, exceeding that in the liver. Moderate DNAase activity, similar to that in the liver, was also seen in the bone marrow as well as in the lung.
