Tiopronin-d₃is intended for use as an internal standard for the quantification of tiopronin by GC- or LC-MS. Tiopronin is an antioxidant that has diverse biological activities.^1,2,3,4,5It reduces free radical production by murine macrophages and granulocytesin vitroin a dose-dependent manner.¹Tiopronin induces expression of hypoxia-inducible factor 1α (HIF-1α) and increases VEGF secretion in human colon carcinoma cells.²Rectal administration (500 μl of a 10 mM solution) reduces myeloperoxidase activity and reduces pro-inflammatory cytokine production in the colon in a rat model of colitis. Tiopronin (80-320 mg/kg per day) reduces the incidence of cleft palate in fetuses born to female mice orally exposed to teratogenic methylmercury chloride.³Tiopronin (100 mg/kg) reduces heme oxygenase 1 mRNA expression, lipid peroxidation, and transverse aortic constriction in a mouse model of cardiac hypertrophy.⁴Tiopronin (20 mg/kg) is hepatoprotective, increasing activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase and reversing hepatocyte degeneration in a rat model of high-fat diet-induced non-alcoholic steatohepatitis.⁵

1.Rommain, M., Delecoeuillerie, G., Paul, J.L., et al.Inhibitory action of tiopronin on free radicalsRev. Rhum. Mal. Osteoartic.56(5 Pt 2)34-37(1989) 2.Yum, S., Park, H., Hong, S., et al.N-(2-mercaptopropionyl)-glycine, a diffusible antioxidant, activates HIF-1 by inhibiting HIF prolyl hydroxylase-2: Implication in amelioration of rat colitis by the antioxidantBiochem. Biophys. Res. Commun.443(3)1008-1013(2014) 3.Fujimoto, T., Fuyuta, M., Kiyofuji, E., et al.Prevention by tiopronin (2-mercaptopropionyl glycine) of methylmercuric chloride-induced teratogenic and fetotoxic effects in miceTeratology20(2)297-301(1979) 4.Date, M.O., Morita, T., Yamashita, N., et al.The antioxidant N-2-mercaptopropionyl glycine attenuates left ventricular hypertrophy in in vivo murine pressure-overload modelJ. Am. Coll. Cardiol.39(5)907-912(2002) 5.Wang, J.Q., Zou, Y.H., Huang, C., et al.Protective effects of tiopronin against high fat diet-induced non-alcoholic steatohepatitis in ratsActa. Pharmacol. Sin.33(6)791-797(2012)