Studies on cell proliferation and tracer localization in the kidneys of guinea pigs with experimental autoimmune anti-tubular basement membrane nephritis

The mitotic activity in kidneys of guinea pigs with experimental autoimmune anti‐tubular basement membrane (TBM) nephritis was investigated using autoradiographic techniques to determine the uptake of [3H]thymidine by actively dividing cells. It was observed in these animals that cells of proximal tubules, distal tubules, cortical and medullary interstitium, medullary collecting ducts, and loops of Henle took up significantly greater amounts of [3H]thymidine when compared with normal animals. In addition, the behaviour of horseradish peroxidase (HRP) and goat anti‐HRP IgG in extraglomerular sites in the kidneys of these animals was studied. Contrary to what was expected, these tracers appeared to be less concentrated in the tubules and interstitium of animals with anti‐TBM disease, with tracer movement restricted in areas of disrupted TBM. The significance of these observations is discussed.