For example, the decrease in PCs after Li treatment results in polyuria (Christensen et al., 2004) since PCs regulate water balance, while the decrease in ICs by Tfcp2l1 deletion enhances kidney infection since ICs mediate urinary acidification and the production of a number of antimicrobials including Lcn2/NGAL (Shohl and Janney, 1917; Paragas et al., 2014). This evidence concerns the gene LCN2 and pyelonephritis.