A mineralocorticoid secreted by the zona fasciculata of the adrenal gland; biosynthesis is regulated by ACTH as well as angiotensin II, which increases 18-OH-DOC production in isolated human adrenal glomerulosa cells; an intermediate in the metabolism of progesterone; can be formed via conversion of DOC in human SK-MEL188 melanoma cells; can be converted to aldosterone by the capsular portion of rat adrenal glands; increases systolic blood pressure in uninephrectomized saline-drinking rats at 200 μg/rat per day; plasma levels of 18-OH-DOC are elevated in a db/db mouse model of type 2 diabetes