6-Ketoprostaglandin F1 alpha: The physiologically active and stable hydrolysis product of EPOPROSTENOL. Found in nearly all mammalian tissue.Thromboxane B2: A stable, physiologically active compound formed in vivo from the prostaglandin endoperoxides. It is important in the platelet-release reaction (release of ADP and serotonin).Thromboxanes: Physiologically active compounds found in many organs of the body. They are formed in vivo from the prostaglandin endoperoxides and cause platelet aggregation, contraction of arteries, and other biological effects. Thromboxanes are important mediators of the actions of polyunsaturated fatty acids transformed by cyclooxygenase.Epoprostenol: A prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. It is biosynthesized enzymatically from PROSTAGLANDIN ENDOPEROXIDES in human vascular tissue. The sodium salt has been also used to treat primary pulmonary hypertension (HYPERTENSION, PULMONARY).15-Oxoprostaglandin 13-Reductase: (5Z)-(15S)-11 alpha-Hydroxy-9,15-dioxoprostanoate:NAD(P)+ delta(13)-oxidoreductase. An enzyme active in prostaglandin E and F catabolism. It catalyzes the reduction of the double bond at the 13-14 position of the 15-ketoprostaglandins and uses NADPH as cofactor. EC A group of compounds derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway. They are extremely potent mediators of a diverse group of physiological processes.