THE DIURETIC EFFECT OF BOROCAPTATE SODIUM IN RATS AND IN PATIENTS WITH BRAIN-TUMORS

Kidney function changes after single-dose administration of borocaptat e sodium were studied in rats and in patients with brain tumors. Chang es of filtration rate (GFR) measured C-14-inulin clearance and urine f low rate (UFR) after a slow intravenous injection of BSH (25 and 50 mg /kg b.w., respectively) were investigated in rats and pentobarbital an esthesia. The effect of BSH has been compared with that of its disulfi de (BSSB) which is spontaneously generated by oxidation of BSH during storage. It was found that BSH decreases GFR in relation to dose and, in the same way, causes a temporary increase of UFR. On the other hand , BSSB (50 mg/kg) induced a large reversible decrease of GFR as well a s a decrease of urine excretion. Measurements of GFR (inulin clearance ), renal plasma flow (PAH clearance) and urine excretion were taken in a group of patients with brain tumors in which boron disposition afte r an infusion of BSH (25 mg/kg b.w. over 1 h) had been studied. An inc rease in urine production was the dominant effect (up to 200% of the i nitial value), with the alterations of GFR and RPF being of minor sign ificance except in one patient with a GFR reduction up to almost 50% t he original value. Kidney function changes after BSH or BSSB administr ation are supposedly related to the high retention of BSH in kidney.