Effect of nabumetone on the renal function in conscious and anesthetized rats

OBJECTIVE: To examine the effect of nabumetone on the renal function in conscious and anesthetized rats.
MATERIAL AND METHODS: For the conscious study, rats were housed individually in metabolic chambers for a duration which consisted of acclimatization, control, experimental and a recovery phase comprising 1, 1, 2 and 1 week respectively. During the experimental phase, one group of rats received nabumetone orally and the controls received an equivalent volume of saline. Water and food intake, body weight, urine output, urine osmolality, osmolal output and electrolyte excretions were estimated. In the second study, rats were anesthetized and saline diuresis in these animals was established with an intravenous infusion of 0.9% saline containing 3H-Inulin. Glomerular filtration rate (GFR) was estimated using standard inulin clearance. The study period consisted of equilibration, control, experimental and a recovery phase comprising 2, 1, 1, and 1 hour respectively. During the experimental phase, one group of rats received a bolus dose of nabumetone intravenously and the controls received the vehicle. Blood and urine samples were collected for analysis of electrolytes, microalbuminuria and GFR estimation. Data was analyzed using ANOVA for repeated measurements.
RESULTS: In conscious rats, no significant differences were found between the two groups in any of the measured parameters. In anesthetized rats, however, there was a significant but reversible decrease in GFR and sodium excretion in rats receiving nabumetone.
CONCLUSION: In contrast to the suggested renal-sparing effects of COX-2 inhibitors, we have observed renal function being affected with nabumetone during anesthetic stress.