Production and distribution of endogenous sulfur dioxide and its generating enzyme in rats

AIM: To investigate the distribution of endogenous sulfur dioxide (SO2) and its generating enzyme (glutamate oxaloacetate transaminase, GOT) in normal rats. METHODS: Wistar rats were anaesthetized and heart, liver, lung, kidney and vascular tissues (including aorta and pulmonary, mesenteric, kidney and tail arteries) were isolated rapidly. SO2 content was determined by reverse-phase HPLC with fluorescence detection and GOT was detected in various tissues by quantitative real-time RT-PCR and enzymatic methods. GOT mRNA expression in arteries was studied through in situ hybridization. RESULTS: SO2 was endogenously generated in various rat tissues, including heart, liver, lung, kidney and arteries. The SO2 content was higher in arteries than that in other tissues. GOT enzyme and GOT mRNA expression were higher in heart, liver and kidney than those in arteries, and GOT1/GOT2 mRNA located in endothelia and vascular smooth muscle cells near endothelial layer. CONCLUSION: SO2 is endogenously generated in cardiovascular system, and the SO2 content in arteries is higher than that in other organs. GOT enzyme and GOT mRNA expression are low in arteries, and this phenomenon may be related with local metabolism.