AngiotensinII is a potent direct vasoconstrictor, causing arteries and veins to constrict, so leading to an increase in blood pressure. Angiotensin also potentiates the release of norepinephrine by a direct action on postganglionic sympathetic fibers.
4-hydroxy Valsartan is a major metabolite of the angiotensinII type 1 (AT1) receptor antagonist valsartan . It reduces platelet aggregation induced by epinephrine and collagen but not ADP in human whole blood.
Telmisartan acyl-β-D-glucuronide is a major metabolite of the angiotensinII receptor antagonist telmisartan . It does not bind human serum albumin and is cleared from rat plasma with a clearance rate of 180 ml min kg following intravenous administration.
Prostaglandin A1 (PGA1) was first isolated as a dehydration product of the PGE1 compounds found in human semen. 15-keto PGA1 is a metabolite of PGA1, produced by 15-hydroxy PG dehydrogenase. It can be produced from PGA1 in pig lung, trachea, aorta, and pulmonary artery tissue preparations. 15-keto PGA1, given at a concentration of 6 μM, causes vasoconstriction of rabbit lung that is comparable to that induced by angiotensinII.
18-Hydroxy-11-deoxy Corticosterone (18-OH-DOC) is a mineralocorticoid produced by the zona fasciculata of the adrenal gland, with its biosynthesis regulated by adrenocorticotropic hormone (ACTH) and angiotensinII. This regulation heightens 18-OH-DOC production in isolated human adrenal glomerulosa cells and allows for its formation from 11-deoxy corticosterone (DOC) in human SK-MEL188 melanoma cells. As an intermediate in progesterone metabolism, 18-OH-DOC can be converted to aldosterone in rat adrenal glands' capsular portion. Its continuous infusion (200 μg rat per day) has been shown to raise systolic blood pressure in uninephrectomized saline-drinking rats, and elevated plasma levels of 18-OH-DOC have been observed in the adb db mouse model of type 2 diabetes.