Effect of Cisplatin on Proximal Convoluted and Straight Segments of the Rat Kidney1

The immediate effect of cisplatin on rat proximal tubular function was investigated by two different methods, the lithium clearance method and the occlusion time-transit time method (TT-OT). Within minutes after administration of cisplatin a significant in-crease in lithium clearance, fractional lithium clearance (C/C) and e#{176}Twas observed (from 270 ± 32 to 387 ± 60 l/min/g kidney weight, 0.202 ± 0.03 to 0.340 ± 0.06 and 0.41 5 ± 0.02 to 0.497 ± 0.02, respectively). These increases indicate an increased fluid delivery from both the proximal straight segment and the late proximal convoluted tubule after cisplatin adminis-tration. Concomitantly absolute proximal reabsorption rate was significantly decreased. Intervention by saline loading (2 % of body weight) did not prevent the increase in e#{176}T, but the increase in C/C was significantly less than in the control group