Insulin receptor-related receptor in rat islets of Langerhans.

The physiological aspects and roles of the insulin receptor-related receptor (IRR), a novel member of the insulin receptor family, are unknown. Published work shows a characteristic localization of IRR mRNA at the cellular level in the kidney, stomach and brain. In our previous study, a specific antibody against the rat IRR beta subunit was generated and used to identify the IRR-expressing cells as B-type intercalated cells in the kidney. In this study. IRR cDNA was amplified by PCR to demonstrate IRR mRNA expression in the rat pancreas. Immunohistochemical analysis with the anti-IRR antibody revealed that IRR immunoreactivity is localized in the islets of Langerhans. The IRR-immunoreactive cells were most likely to be the islet B cells which were stained with anti-insulin antibody. This is the first finding on the involvement of IRR in the physiological functions of insulin-secreting cells.