When we compared the 1st and 2nd Gd-DTPA concentration curve profiles from blood, brain tumor, and skeletal muscle, it became apparent that the extent of the increase in the half-life of Gd-DTPA within blood, brain tumor, and skeletal muscle correlated with the known metabolic stabilities of the respective bradykinin B2 receptor agonists. The gene discussed is BDKRB2; the disease is brain neoplasm.