Effect of furosemide on transperitoneal passage of uric acid--experimental studies

Application of furosemide (F) during peritoneal dialysis had been proposed for enlargement of peritoneal excretion of uric acid (UA), however, localization and mechanism of action of the drug remained obscure. To clarify the problem experimental studies on isolated peritoneum were performed with intention to establish whether and how transperitoneal flux of UA can be modified by F. Experiments were carried out in vitro on fragments of peritoneum taken from rabbits: parietal peritoneum and mesentery were isolated with single layer of mesothelium, and minimal amount of submesothelial tissue. Gradient of UA across the membranes was set up at 0.9-1.1 mmol/l, and flow estimated before and after addition of F (final conc. 10(-4) M) to the medium bathing either side of the membranes. Some differences in the flow between both types of the membranes as quantitative (greater flow in the parietal peritoneum), and qualitative (opposite succession of changes after F) were observed, however, the reaction for the diuretic was significant in both series of the experiments. The results confirm the suggestion that F can affect peritoneal excretion of UA during the dialysis, but at the same time they show that the mechanisms regulating the transperitoneal UA passage are complex.