Involvement of the Kidney in Catabolism of Human Leukocyte Interferon Bino, Tamar and Edery, Habib and Gertler, Arieh and Rosenberg, Hagai,, 59, 39-45 (1982), doi = https://doi.org/10.1099/0022-1317-59-1-39, publicationName = Microbiology Society, issn = 0022-1317, abstract= SUMMARY The metabolic fate of human leukocyte interferon (HuIFN-α) was studied after intravenous injection into rats and cynomolgus monkeys. At various intervals the animals were sacrificed and the HuIFN-α content determined in serum and various tissues. HuIFN-α quickly disappeared from the circulation and was found mainly in the kidneys, in which levels were at least 7- to 10-fold higher than in the liver, spleen, lungs, heart, brain and muscles. No interferon was detected in urine. Subcellular fractionation of kidney revealed that the mitochondrial-lysosomal fraction (15000 g) had a high HuIFN-α content. It was also found that HuIFN-α was rapidly inactivated by two types of proteinases found in the lysosomal fractions of rat, monkey and human kidneys, with an optimal pH of 3 to 4. The inactivation was partially inhibited by either pepstatin or leupeptin. Inactivation was totally prevented by a mixture of both inhibitors. Since it is known that interferon is scantily excreted in urine, our findings suggest that the kidney serves as a main site for its degradation., language=, type=