An aging clock may be located in the pituitary. Important in blood coagulation. They are tiny fragments of cells derived form the bone marrow. Lipid peroxides stimulate platelets to make thromboxane A2, which in turn causes platelets to adhere and aggregate, as in the formation of atherosclerotic placques and clotting. These are probably the most important human chemical carcinogens and are suspected of being responsible for many of human cancers other than solar ultraviolet induced skin cancers.
Tobacco smoke is by far the most important source of humans.
They are also found in relatively large quantities on charcoal broiled meats. Antioxidants can protect these polyunsaturated fats from such chemical attacks. Victims generally die before their teens of strokes or heart attack, looking like little old men or women, bald, bent over, with wrinkled faces, and so on. Used to treat menstrual disorders, among other problems. Peroxidized lipids can block prostacyclin manufacture, thus fostering the development of blood clots.