8–37h‐CGRP antagonizes actions of amylin on carbohydrate metabolism in vitro and in vivo

Abstract
8–37hCGRP is a potent antagonist at calcitonin gene‐related peptide (CGRP) liver membrane receptors; it also blocks vasodilator actions of CGRP and the related peptide, amylin, in intact rats. We now report that 8–37hCGRP antagonizes amylin inhibition of insulin‐stimulated labelled glucose uptake into isolated rat soleus muscle, and inhibits amylin‐evoked elevation of plasma lactate and glucose in fasted anaesthetized rats. The different relative potencies of the 3 ligands (amylin, CGRP, 8–37hCGRP) on the liver receptor and on the soleus muscle point to distinct CGRP receptors in liver membranes and amylin receptors on muscle cells.