High-performance liquid chromatographic determination of hypotaurine and taurine after conversion to 4-dimethylaminoazobenzene-4'-sulfonyl derivatives and its application to the urine of cysteine-administered rats.

A method for the determination of urinary hypotaurine and taurine for the purpose of studying hypotaurine-taurine status in mammals is described. Hypotaurine and taurine were converted into 4-dimethylaminoazobenzene-4'-sulfonyl (dabsyl) derivatives under conditions minimizing hypotaurine oxidation. The dabsylhypotaurine and dabsyltaurine formed were determined by reversed-phase HPLC. Average excretions of taurine and hypotaurine in rat urine were 270.5 and 2.5 mumol/kg body mass per day, respectively. After intraperitoneal injection of 5 mmol of L-cysteine/kg body mass, the increased excretions of taurine and hypotaurine corresponded to 22.1 and 2.5%, respectively, of L-cysteine administered, indicating that hypotaurine production exceeded the capacity of hypotaurine oxidation in vivo.