Isolation and Characterization of Coenzyme A Glutathione Disulfide as a Parathyroid-Derived Vasoconstrictive Factor

Abstract

Background —Coenzyme A glutathione disulfide (CoA-SSG) was recently isolated from bovine adrenal glands and was shown to be a renal vasoconstrictor. The identification of CoA-SSG in human parathyroid glands and its action on cultured vascular smooth muscle cells (VSMCs) are described here. Methods and Results —After purification to homogeneity by several chromatographic steps, CoA-SSG was identified by matrix-assisted laser desorption/ionization mass spectrometry and enzymatic analysis. The dose-dependent growth-stimulating effect of CoA-SSG on VSMCs, measured by the [ 3 H]thymidine method, is characterized by a threshold of 10 − 8 mol/L and a maximum effect of 10 μmol/L, increasing VSMC proliferation 254±21% above control. A dose of 10 μmol/L methylmalonyl-CoA and 10 μmol/L CoA increased the rate of proliferation of VSMCs only by 178±43% and 50±42% above control, respectively. Glutathione has no proliferative effect on VSMCs. The growth-stimulating effect of CoA-SSG (1 μmol/L) was decreased by the antagonists 3,7-dimethyl-1-propargylxanthine (DMPX; 11 μmol/L) (38% compared with CoA-SSG without antagonist) and pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid (PPADS; 10 μmol/L) (48% compared with CoA-SSG without antagonist; each P <0.05 versus control), indicating that the effect is mediated partly via A 2 and partly via P 2 Y 1 and/or P 2 Y 4 receptor. Conclusions —CoA-SSG may play a regulatory role in VSMC growth as a progression factor and thereby could play an important role in development of hypertension.