The Regulation of Catecholamine Biosynthesis by the Gas Transmitters Carbon Monoxide and Hydrogen Sulfide.

The gas transmitters nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S) play important roles in physiological regulation, including adrenal function. Among them, only NO has been directly implicated in controlling catecholamine biosynthesis. This study examined whether CO and H₂S exert similar effects by treating PC12 cells with a CO donor (CORM-2) or an H₂S donor (NaHS), with or without glucocorticoid stimulation. Gene expression of tyrosine hydroxylase (Th), dopamine β-hydroxylase (Dbh), and phenylethanolamine N-methyltransferase (Pnmt) was assessed by RT-qPCR, and catecholamine release was measured by ELISA. We found that exogenous CO decreased Th and Dbh expression, attenuated glucocorticoid-induced upregulation of catecholamine biosynthesis genes, and differentially modulated dopamine and norepinephrine release. In contrast, exogenous H₂S treatment had no significant effect. These findings identify CO as a novel regulator of catecholamine biosynthesis and highlight important differences among gas transmitters in stress-related signaling.