Over-the-Counter Market. 1  Describing a security or trade that does not occur on an exchange. Very often, the OTC market includes securities that are very small and do not trade on an exchange because they do not meet market capitalization requirements. 2  A widespread aggregation of dealers who make markets in many different securities.
Liver tests check the blood for two main liver enzymes: 1  Aspartate aminotransferase (AST), formerly called SGOT; the AST enzyme is also found in muscles and many other tissues besides the liver. 2  Alanine aminotransferase (ALT), formerly called SGPT; ALT is almost exclusively found in the liver.
But when the liver is injured, these enzymes are spilled into the blood stream. Among the most sensitive and widely used of these liver enzymes are the aminotransferases. They include GGT, aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). These enzymes are normally contained within liver cells. If the liver is injured, the liver cells spill the enzymes into blood, raising the enzyme levels in the blood and signaling the liver damage.