Cyclic Amp (Cyclic Adenosine Monophosphate)
Cyclic AMP was the first chemical to be isolated and identified as a second messenger--a substance produced by a cell when a hormone or other chemical (the first messenger) binds to specific receptor sites on the cell surface. The second messenger, in turn, influences the cell's processes. The discovery was a major step toward understanding how both hormones and cells function.
Until 1956, scientists thought that hormones performed their action on cells directly. Then the American physician and pharmacologist Earl Sutherland showed that hormones stimulate production by the cell of cyclic AMP (adenosine-3',5' -phosphoric acid), which effects the cell's activity. He received the 1971 Nobel Prize in physiology or medicine for his work.
Sutherland was born and raised in Burlingame, Kansas. He graduated from Washburn University in Topeka and received his M.D. from Washington University in St. Louis, Missouri. From there, Sutherland went on to conduct his research at Washington University and Case Western Reserve University, and was a faculty member at Vanderbilt University and the University of Miami.
Sutherland investigated the active and inactive forms of the enzyme phosphorylase, whose active form begins the breakdown of glycogen stored in the liver and muscle into glucose. He also co-discovered the source of the hormone glucagon in the pancreatic islet of Langerhans cells, and investigated how glucagon and another hormone, epinephrine, cause the liver's release of glucose.
Sutherland and a colleague observed that inactive phosphorylase became active in the presence of an unrefined liver extract, but not when impurities were filtered from it. Next they added epinephrine and glucagon to the material removed during refinement. The result was a substance that in turn activated phosphorylase. Sutherland's research group and another group of scientists independently isolated cyclic AMP as the activating substance, which Sutherland designated a "second messenger."
It was soon demonstrated that cyclic AMP also worked as a second messenger with other hormones and in many other tissues in different species. Further, it could either stimulate or inhibit cell activity. Subsequent research has discovered the second-messenger function of other chemicals, as well, including cyclic GMP (guanosine 3',5 '-cyclic monophosphate), discovered by Sutherland.
Cyclic AMP has been shown to be an important link in many processes, such as memory and hormonal response. In 1998, scientists at the University of California at San Francisco discovered a possible link between a person's cyclic AMP levels and tolerance to alcohol- a factor which may prove important in determining the genetic predisposition to alcoholism. Further studies are necessary before this theory of cyclic AMP involvement is proven.
This is the complete article, containing 419 words
(approx. 1 page at 300 words per page).
