The influence of a nitric oxide synthase inhibitor and endothelin receptor blocker on the free sulfhydryl groups content in lung homogenates.

INTRODUCTION The aim of the study was to assess the influence of the nitric oxide synthase inhibitor L-NAME and the endothelin receptor blocker BQ123 on the free sulfhydryl (-SH) groups content in rat lung homogenates. MATERIAL AND METHODS Experiments were performed on Wistar-Kyoto rats divided into the following groups: group I (control) received (i.v.) saline; group II (ET-1) received (i.v.) endothelin 1 (3 g μg/kg b.w.); group III (BQ123+ET-1) received (i.v.) ET(A) receptor blocker (1 mg/kg b.w.) + endothelin 1 (3 g μg/kg b.w.); group IV (L-NAME+ET-1) received (i.v.) nitric oxide synthase inhibitor (5 mg/kg b.w.) + endothelin 1 (3 μg/kg b.w.). RESULTS Administration of BQ123 at a dose of 1 mg/kg b.w. resulted in a statistically significant increase in the concentration of -SH groups (p<0.001 vs. ET-1). L-NAME (5 mg/kg b.w.) also significantly increased the level of -SH groups in the lungs of rats during oxidative stress induced ET-1 (p<0.001). DISCUSSION The nitric oxide synthase inhibitor L-NAME at a dose of 5 mg/kg b.w. and the endothelin receptor blocker BQ123 at a dose of 1 mg/kg b.w. showed a significant increase in the concentration of -SH groups in the lungs, which may be associated with an increase in synthesis of proteins containing sulfhydryl groups.