A high-performance liquid chromatographic (HPLC) assay method has been developed for the quantitative determination of iothalamate and p-aminohippuric acid (PAH) concentrations in serum and urine samples in the male rat. Glomerular filtration rate (GFR) was measured as clearance of iothalamate, while effective renal blood flow (ERBF) was measured as clearance of PAH. The method is simple, rapid and sensitive and detects iothalamate and PAH in rat serum and urine following administration of bolus doses and continuous infusions of iothalamate and PAH. Samples of serum and urine were deproteinized with two volumes of acetonitrile containing the internal standard, and an aliquot chromatographed on a C18 reversed-phase column. The mobile phase was comprised of 0.1 M sodium phosphate with 1.2 mM tetrabutylammonium phosphate: methanol, 85:15 (v/v), at a flow rate of 1.0 mL/min. The analytical column eluate was monitored with a UV detector at 254 nm with quantitation achieved using peak-height ratios. The precision of the method was 6.6 and 3.6% for iothalamate in serum and urine, and 5.6 and 4.9% for PAH in serum and urine, respectively. The lower limit of quantitation was 0.63 microgram/mL for iothalamate and 1.25 microgram/mL for PAH in serum, and 3.1 microgram/mL for iothalamate and 1.5 microgram/mL for PAH in urine. Recovery of iothalamate from serum and urine was 99.9 and 93.5%, respectively. Recovery of PAH from serum and urine was 99.8 and 92.6%, respectively. The present study demonstrated that non-radioactive iothalamate and PAH can be measured simultaneously using a HPLC assay to measure GFR and ERBF in the male rat.

Animals↗

PubMedDate not supplied

Renal papillary necrosis and urinary protein alterations induced in Fischer-344 rats by D-ormaplatin.

D-ormaplatin (previously called tetraplatin) produced dose-related renal papillary necrosis when given intravenously to Fischer-344 rats at doses of 2, 4, and 9 mg/kg. The lesions were most severe at 4 days postdosing and had repaired by day 9 in the 2- and 4-mg/kg dose groups. Blood urea nitrogen and the N-acetyl-beta-glucosaminidase (NAG): creatinine ratio were slightly elevated at day 4 while creatinine clearance was decreased. Body weight was reduced in a dose-related manner while kidney weights increased. Total protein excretion in male and female rats was elevated at day 4 postdosing. The evaluation of urinary proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed an increase, primarily in high molecular weight proteins at 4 days postdosing, indicating an increase in glomerular filtration of albumin and transferrin. The morphologic appearance of the glomeruli was normal by light microscopy. At day 4 postdosing, alpha 1-microglobulin was elevated. This correlated with an increase in the NAG: creatinine ratio also seen at this time and the morphologic appearance of the kidney, indicating that the proximal tubules were affected but were not a major site of toxicity. Although the change in urinary proteins occurred at the same time as morphologic alterations in the renal papilla, these findings were not considered to be related. SDS-PAGE provided a useful method for detecting and localizing renal toxicity when used in conjunction with morphologic and clinical chemistry methods.

Acetylglucosaminidase↗