PNMT (phenylethanolamine N-methyltransferase) catalyzes the final step of epinephrine biosynthesis, transferring a methyl group from S-adenosyl-L-methionine to norepinephrine 1. The enzyme also methylates other phenylethanolamine substrates including octopamine and normetanephrine 234. PNMT functions primarily in chr17 cells of the adrenal medulla, making the adrenal gland the body's primary epinephrine source 5. A recently identified cardiac subpopulation of PNMT-derived cardiomyocytes suggests broader physiological roles in intra-cardiac adrenergic signaling 6. PNMT expression is regulated by glucocorticoids and transcription factors including Egr-1, AP2, Sp1, and MAZ 5. In pheochromocytomas, PNMT marks kinase-type tumors displaying decreased epinephrine synthesis and neuron-like phenotypes 7. Epinephrine dysregulation via altered PNMT expression associates with blood pressure regulation, respiration, Alzheimer's disease, and post-traumatic stress disorder 89. Promoter methylation of PNMT inversely correlates with catecholamine secretion patterns in pheochromocytomas and paragangliomas, indicating epigenetic control of enzyme expression 10. PNMT represents a candidate gene in essential hypertension pathogenesis 11.