Renal amyloidosis in KK mice that may be misinterpreted as diabetic glomerulosclerosis

A normoglycemic, normoinsulinemic, "lean" phenotype KK mouse having a morphologically normal pancreatic islet had renal lesions reminiscent of diabetic glomerulosclerosis described in the literature for KK mice. Most of these animals also had splenomegaly. Using histochemical and ultrastructural methods, the renal and splenic lesions were demonstrated to be amyloidotic. Extensive deposits of amyloid were found in the liver and adrenals. Amyloidosis was found in all lean KK mice 4 months of age or older and in five of 11 C57BL/6J mice over 1 year of age. The validity of data attributing glomerulosclerosis to diabetes in mice that are neither glucosuric nor hyperglycemic or that show normal tolerance to glucose load should be questioned until amyloidosis is ruled out.