Renal handling of uric acid assessed by means of pharmacological tests in obese women.

The aim of this study was to compare the renal handling of uric acid by means of pyrazinamide and probenecid tests between obese and non-obese women. A cross-sectional study was carried out in 8 obese women and in 8 non-obese women as control group. Metabolic profile and renal handling of uric acid including clearance, fractional excretion and excretion rates, were assessed. Due to technical problems, pyrazinamide and probenecid tests were performed only in 5 women of each group to evaluate presecretory reabsorption, secretion and post-secretory reabsorption of uric acid. Uric acid clearance had a tendency to be lower in the obese women than in the control group. There were no significant differences between the groups in fractional excretion and excretion uric acid rates. Pre- and post-secretory reabsorptions of uric acid did not differ between the obese and the non-obese women. Tubular secretion of uric acid was significantly lower in the obese women compared with the control group (6.4 vs 13.6%; p=0.02). Tubular secretion of uric acid negatively correlated with body mass index (r=-0.73; p<0.05). In conclusion, tubular secretion of uric acid possibly plays an important role in uric acid homeostasis in obese women.