CBS and colitis: Treatment with a nonspecific CTH inhibitor propargylglycine exacerbated DSS-induced colitis in mice [33], and mRNA expression of three H2S-producing enzymes (CTH, MPST, and cystathionine β-synthase [CBS]) and H2S production was upregulated in the colon mucosa in the experimental colitis of mice/rats [29,33,34,35].