Inhibitory Effect of 6-Aminonicotinamide on the Renal Transport of Para-Aminohippurate in the Rat

Abstract

The effect of 6-aminonicotinamide (6-AN), a typical potent inhibitor of the pentose phosphate pathway, on the renal transport of p-aminohippurate (PAH) was investigated in the rat. The contents of ATP and 6-phosphogluconate (6-PG) in the kidney were measured at intervals of 2 h after the administration of 6-AN (75 mg/kg body wt i.p.). The 6-PG content in the kidney rapidly increased, and it reached a plateau at the 4th h after administration; this level was maintained up to the 8th h. The ATP content remained normal up to the 6th h, after which it significantly decreased as time elapsed. Additional experiments were carried out by loading the rat with a high concentration of PAH solution at 6 h after the administration of 6-AN. The renal tubular secretion maximum for PAH was significantly depressed in the 6-AN group, in comparison to the control. This depression in renal PAH secretion capacity was partially due to the inhibition of the pentose phosphate pathway in the kidney, but not due to the change of renal ATP level.