S-Adenosyl methionine (SAM, SAMe, SAM-e) is a coenzyme involved in methyl group transfers. SAM was first discovered in Italy by G. L. Cantoni in 1952. It is made from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase. Transmethylation, transsulfuration, and aminopropylation are the metabolic pathways that use SAM. Although these anabolic reactions occur throughout the body, most SAM is produced and consumed in the liver. In the United States, SAM is sold as a nutritional supplement under the marketing name SAM-e (also spelled SAME or SAMe; pronounced "sam ee"). SAM is also marketed under the Gumbaral, Samyr, Adomet, Heptral and Admethionine brand names as a prescription drug approved in Russia, Italy, and Germany. Some research has indicated that taking SAM on a regular basis may help fight depression, liver disease, and the pain of osteoarthritis.[10] Multiple clinical trials indicate benefits for depression, some liver conditions and osteoarthritis. All other indications are not yet proven. Therapeutic use of SAM has increased as dietary supplements have gained in popularity, especially after the Dietary Supplement Health and Education Act was passed in 1994. This law allowed the distribution of SAM as dietary supplement, and therefore allowed it to bypass the regulatory requirements for drugs of the Food and Drug Administration (FDA). At first, a line of evidence suggested that abnormally low levels of endogenous SAM may play an important role in the development of Alzheimer's disease (AD) and that SAM may therefore have therapeutic potential in the treatment of AD. However, further research has indicated this effect is likely due to vitamin B12 deficiencies, which cause neurologic defects through one carbon transfers with folate. Severely low levels of SAM have been found in the cerebrospinal fluid and in all brain regions of AD patients examined. Preliminary research suggests SAM may have therapeutic potential in treating AD patients and a recent study using a mouse model of AD found that supplementary SAM prevented oxidation.