Figure 4. The effect of the calcium antagonist diltiazem in preventing radiographic contrast medium induced-nephropathy in rats pre-treated with indomethacin and L-nitroarginine methyl ester (L-NAME). (a) Serum creatinine(Cr) before () and 24 h after () injection of 6 ml diatrizoate in rats following intraperitoneal injection of either 4 ml of normal saline (Group 1) or diltiazem (Group 2, 2 mg kg^-1; Group 3, 6 mg kg^-1; or Group 4, 10 mg kg^-1). Significant increase (^*p<0.01) in serum Cr occurred in Groups 1, 2 and 3 but no significant rise occurred in Group 4 (n=5 per group). Comparison of the percentage rise in serum Cr from baseline between groups was: Group 1>Group 2 (p<0.05), Group 2>Group 3 (p<0.05) and Group 3>Group 4 (p<0.01). (b) Percentage change in Cr clearance from baseline (24 h pre injection) to 24 h post injection of 6 ml diatrizoate in rats with introperitoneal injection of either 4 ml of normal saline (Group 1) or diltiazem (Group 2, 2 mg kg^-1; Group 3, 6 mg kg^-1; or Group 4, 10 mg kg^-1). Significant decreases (^*p<0.01) in Cr clearance occurred in all groups (n=5 per group). The smallest reduction occurred in Group 4. The extent of reduction was: Group 2>Group 3 (p<0.01), Group 3>Group 4 (p<0.01). No significant difference was found between Groups 1 and 2.