PROSTAGLANDIN

Chemical structure of prostaglandin. any of a group of physiologically active substances having diverse hormonelike effects in animals. In terms of chemical structure, prostaglandins are 20-carbon fatty acid derivatives containing a 5-carbon ring. They were discovered in human semen in 1935 by the Swedish physiologist Ulf von Euler, who named them thinking that they were secreted by the prostate gland. Prostaglandins are now known to be of widespread occurrence in animal tissues, where they are formed from polyunsaturated fatty acids and are rapidly metabolized. Prostaglandins are very potent: some affect human blood pressure at concentrations as low as 0.1 microgram per kilogram of body weight. They also are diverse in their effects. Depending on their type, prostaglandins can stimulate smooth-muscle contraction; lower and, in some animals, raise blood pressure; decrease and increase the clotting ability of blood; enhance ion transport across some membranes; stimulate inflammation; and inhibit lipolysis (the breakdown of fat) in adipose tissue. A given prostaglandin may have different and even opposite effects in different tissues. The understanding of prostaglandins grew in the 1960s and '70s with the pioneering research of biochemists Sune K. Bergstrm and Bengt Ingemar Samuelsson of Sweden and John Robert Vane of Britain. The threesome shared the Nobel Prize for Physiology or Medicine in 1982. Prostaglandins continue to receive much attention, partly because of their potential therapeutic value, which includes control of cardiovascular disease and virus infections; they may be useful as contraceptives and in producing abortions in humans and livestock. Substances that inhibit prostaglandin synthesis may be useful in controlling pain, asthma attacks, and anaphylactic shock and in reducing the clotting ability of blood.