Calcitonin gene related peptide (CGRP) is a potent vasodilator, and also elicits a number of other biological effects. Average plasma levels of CGRP have been reported to be from 0.8 pmol/L to 71 pmol/L (3 pg/ml to 269 pg/ml) in normal subjects. Increases in circulating CGRP levels have been noticed during hemodialysis, pregnancy, exacerbation of asthma, and in cases of medullary thyroid carcinoma.