The immunocytochemical demonstration of renin in a juxtaglomerular cell tumour by light and electron microscopy

This is a study of a juxtaglomerular cell tumour using an antibody to pure human renin and the peroxidase-antiperoxidase technique. We report the distribution of immunoreactive renin in the tumour visualized by light microscopy of both paraffin and resin embedded tissue sections. We found that the cells which contained most renin granules were endocrine-like cells in the parenchyma of the tumour. Ultrastructural immunocytochemistry showed that immunoreactive renin was present not only in crystalline protogranules and in round membrane bound granules, but also in intermediate forms.