Physiologically significant mineralocortocoids and glucocorticoids were believed to be synthesized only in the adrenal cortex. We have reported the biosynthesis of steroid hormones in the vasculature and its patho-physiological roles in the cardiovascular disease. [¹⁴C]-pregnenolone was metabolized to [¹⁴C]-aldosterone or [¹⁴C]-cortisol (corticosterone) in the rat vascular wall and cultured human vascular cells. Messenger RNA (mRNA) for enzymes involved in adrenal steroid biosynthesis were expressed in the blood vessel and in the vascular cells. Angiotensin II and potassium increased the expression of mRNA of CYP11B2 (aldosterone synthase gene) and the activity of aldosterone synthase in the cultured vascular cells. ACTH increased the CYP11B1 mRNA (glucocorticoid synthase gene) expression and the enzyme activity in the cultured vascular cells. Aldosterone, synthesized in the vasculature, contributes to hypertension of the genetically hypertensive rats and vascular hypertrophy.