Effect of calcitonin gene related peptide on the adenylate cyclase activity in abalone gill membranes

The aim of the present study was to investigate and to compare the effect o f calciotropic hormones, human calcitonin gene related peptide (CGRP)I and II, salmon calcitonin (CT) and human amylin on the adenylate cyclase activi ty in abalone gill membranes. In addition to human CGRPI. human CGRPII and salmon CT stimulated the adenylate cyclase activity. No effect was observed with amylin. The higher effect was observed with human CGRPI and II that i nduced a 160-170% increase of the enzyme activity. Fifty percent of the max imal activity was observed with 3 and 8 nM of CGRP I and II, respectively. Salmon CT induced a lower effect: the maximal activity was obtained with a hormone concentration of 266 nM and represented a 130% stimulation of the b asal activity. In the presence of CGRP 8-37, a competitive antagonist of CG RP action, the stimulation observed with CGRPI was abolished and returned t o the basal level. This study points out that, in invertebrates, CGRP receptors present in gil l membranes are linked to an adenylate cyclase system similar to that descr ibed in vertebrates. In addition, these data are in favour of a role for CG RP in branchial function both in non-mammalian vertebrates and invertebrate s (C) 2001 Elsevier Science B.V. All rights reserved.