Protease histochemistry in normal and uremic rats.

In rats, ARF caused protease changes which could be detected histochemically. The organs which clearly responded were the extraorbital gland, thymus and lung (ARF-sensitive organs); the others did not show a clear-cut response (ARF-insensitive organs). In the affected organs activities of plasma membrane-associated and lysosomal proteases were either increased or decreased. The response of the proteases in the extraorbital gland is considered to be specific whereas this in the thymus and lung is not. However, ARF has not a protease-specific effect which can be shown when further groups of enzymes are investigated using histochemical means.