Prostaglandins

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Prostaglandins, in biochemistry and medicine, family of hormonelike chemicals occurring naturally in all mammals (see Biochemistry; Hormone). Prostaglandins, fatty-acid derivatives, are found in almost all tissues in the human body. More than a dozen biologically important forms of prostaglandins occur, affecting many essential physiological functions.

The first uses of prostaglandins were in obstetrics. By constricting blood vessels in the uterus, some prostaglandins stimulate contractions, making them useful in delivery or therapeutic abortion. In the late 1970s this same action was shown to cause the pain and cramping, called dysmenorrhea, that many women experience during the menstrual period. Administration of drugs that inhibit prostaglandin synthesis, such as ibuprofen and naproxen, relieves dysmenorrhea in most cases. The effects of prostaglandins on blood vessels are also thought to cause some migraine headaches.

The two prostaglandins discovered in the 1970s, thromboxane and prostacyclin, were found to affect the clotting ability of blood: one of them (thromboxane) promoting and the other (prostacyclin) inhibiting the clumping of platelets (thrombocytes), the small corpuscles in the blood that aid in wound healing. Because aggregation of platelets is thought to contribute to stroke and heart attacks, prostaglandin-synthesis inhibitors such as aspirin are now being tested for the ability to prevent these events. Prostaglandins also promote inflammation; thus drugs that block prostaglandin synthesis are effective against arthritis and similar diseases.

Prostaglandins block production of gastric acid, and work is progressing on the development of drugs that may prove useful for treatment of peptic ulcer and other conditions caused by gastric hyperactivity.

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