INSULIN RECEPTOR-RELATED RECEPTOR IN RAT ISLETS OF LANGERHANS

The physiological aspects and roles of the insulin receptor-related re ceptor (IRR), a novel member of the insulin receptor family, are unkno wn. Published work shows a characteristic localization of IRR mRNA at the cellular level in the kidney, stomach and brain. In our previous s tudy, a specific antibody against the rat IRR beta subunit Was generat ed and used fn identify the IRR-expressing cells as B-type intercalate d cells in the kidney. In this study, IRR cDNA was amplified by PCR to demonstrate IIR mRNA expression in the rat pancreas. Immunohistochemi cal analysis with the anti-IRR antibody revealed that IRR immunoreacti vity 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 o f IRR in the physiological functions of insulin-secreting cells.