Contribution of renal active secretion in renal excretion of N4-acetylsulfamonomethoxine in conscious pigs.

The contribution of renal active tubular secretion of N4-acetylsulfamonomethoxine (AcSMM) in renal excretion was examined using 3 conscious pigs with permanent ureter cannulae. AcSMM was the main metabolite of sulfamonomethoxine (SMM) in pigs. When AcSMM (100 mg/kg) was intravenously injected, the renal clearance of AcSMM increased with the decrease of AcSMM plasma concentration. Michaelis-Menten kinetics was demonstrated in the renal excretion of AcSMM. It can be concluded that AcSMM is mostly excreted through active tubular secretion. The decrease of renal clearance of AcSMM may be thought as the causal factor of nonlinear plasma kinetics of SMM in pig.