Rat receptor-activity-modifying proteins (RAMPs) for adrenomedullin/CGRP receptor: Cloning and upregulation in obstructive nephropathy

Adrenomedullin (AM) is a potent vasorelaxing peptide originally isolated ph eochromocytoma. Recently, a family of receptor-activity-modifying proteins (RAMPs 1-3) were identified in humans. Associated with the calcitonin recep tor-like receptor (CRLR), RAMP2 or RAMPS may function as the AM: receptor. Here we cloned rat RAMP family, analyzed their distribution in rat tissues, and examined regulation of their expression in the kidney using an obstruc tive nephropathy model. Northern blot analyses revealed that the RAMP famil y genes are expressed in various tissues with different tissue specificity; RAMP1 is abundantly expressed in the brain, fat, thymus, and spleen, RAMP2 in the lung, spleen, fat, and aorta, while RAMP3 is most abundant in the k idney and lung. After ureteral obstruction, RAMP1, RAMPS, and CRLR gene exp ressions in the obstructed kidney were markedly upregulated, whereas RAMP3 expression was unchanged. Thus, RAMPs are regulated differently in obstruct ive nephropathy, suggesting their distinct roles in renal pathophysiology. (C) 2000 Academic Press.