Microscopic evaluation of kidneys from animals administered PG via enteric tablets showed renal nephropathy consisting of tubular degeneration and regeneration and occasionally focal interstitial infiltrates of mononuclear cells or brown-yellow pigment in tubular epithelial cells. In addition, dilation of glomeruli was observed in some affected tubules. Additionally, these animals also had an increase in urine neutrophil gelatinase-associated lipocalin (NGAL) levels, one of the 6 renal injury biomarkers recommended by the FDA for clinical monitoring. Time-dependent increases in NGAL levels were observed in dogs receiving excipients with PG, shown in Figure . Other excipients such as sodium chenodeoxycholate (NaCDC) did not induce NGAL levels. This biomarker correlated well with the histopathological nephropathy observed in these animals.