The current experiments and the previous literature indicate that PACAP should counteract multiple processes that contribute to the pathogenesis of contrast-induced nephropathy, that is, PACAP should reduce the direct toxic effects of iodinated contrast media on renal epithelial and endothelial cells, suppress the innate immune responses in the kidney to iodinated contrast media, and attenuate the decrease in renal blood flow caused by iodinated contrast media. The gene discussed is ADCYAP1; the disease is kidney disorder.