The CGRP-sequence was predicted from the corresponding mRNA. CGRP is present in the C-cells of the thyroid and in nerves, in both brain and periphery, particularly within the sensory system. CGRP is a potent vasodilator, probably involved in neurogenic inflammation. Medullary carcinomas of the thyroid contain large amounts of CGRP. Absorption with 10 – 100 µg CGRP per ml diluted antiserum abolishes the staining while calcitonin, does not. Cross-reacts with amylin (IAPP).Positive control: Stefanini-fixed frozen sections of rat colon.