To determine whether tryptophan metabolism is abnormally regulated in murine PKD, we performed metabolomic analyses of metabolites within the tryptophan pathway using the orthologous ADPKD model C57BL/6J Pkd1 p.R3277C (Pkd1RC/RC) (41, 44, 45). The gene discussed is PKD1; the disease is autosomal dominant polycystic kidney disease.