Immunocytochemical demonstration of mineralocorticoid receptors in rat and human kidney.

Using a polyclonal antiserum against the hinge region of the recently cloned human mineralocorticoid receptor (MR) and indirect peroxidase immunohistochemistry, we have shown MR-like immunoreactivity (LI) in superficial nephron segments, including distal convoluted tubule, connecting piece and initial cortical collecting duct. The absence of staining in cells tentatively identified as intercalated cells on light microscopy was confirmed by pre-embedding electron microscopy. Though the intracellular distribution of immunostaining varied with the fixative used, the cellular distribution of MR-LI is in good general agreement with earlier micropuncture and autoradiographic studies.