Adrenomedullin increases cyclic AMP more potently than CGRP and amylin in rat renal tubular basolateral membranes.
In rat renal tubular basolateral membranes, the potency to increase cAMP of adrenomedullin (AM), a novel vasorelaxant peptide originally isolated from human pheochromocytoma, was compared with those of calcitonin gene-related peptide (CGRP) and amylin. Although all three peptides raised cAMP in a time- and concentration-dependent manner with a 4-fold increase at 10(-6)-10(-5) M, the EC50 value (10(-9) M) of AM was 100-fold smaller than those of CGRP and amylin. CGRP[8-37], an antagonist for CGRP receptors, attenuated cAMP elevation induced by these peptides with the essentially similar concentration-inhibition curves. These results suggest that the receptors for AM, CGRP and amylin share a common structural homology, and that the receptors sensitive to AM are preferentially expressed in renal tubular basolateral membranes.
Osajima
A
A
Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Mutoh
Y
Y
Uezono
Y
Y
Kawamura
M
M
Izumi
F
F
Takasugi
M
M
Kuroiwa
A
A
D053607:Adrenomedullin; D000682:Amyloid / Q000494:pharmacology*; D000818:Animals; D001485:Basement Membrane / Q000187:drug effects / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D058228:Islet Amyloid Polypeptide; D007684:Kidney Tubules / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D000682:Amyloid; D058228:Islet Amyloid Polypeptide; D010455:Peptides; D053607:Adrenomedullin; D000242:Cyclic AMP; D015740:Calcitonin Gene-Related Peptide