Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
The liver is located in the right upper portion of the abdominal cavity just
beneath the right side of the rib cage. The liver has many functions that are
vital to life. Briefly, some
of the important functions of the human liver are:
Detoxification of blood
Production of important clotting factors, albumin, and many other important proteins
Metabolizing (processing) medications and nutrients
Processing of waste products of hemoglobin
and other cells
Storing of vitamins, fat, cholesterol, and bile
Production of glucose (gluconeogenesis or glucose synthesis/release during starvation)
Liver blood tests are some of the most commonly performed blood tests. These tests can
be used to assess liver functions or liver injury. An initial step in detecting liver damage is a simple blood test to determine the
level of certain liver enzymes (proteins) in the blood. Under normal circumstances, these enzymes
mostly reside within the cells of the liver. But when the liver is injured for any reason, these enzymes are spilled into the blood stream. Enzymes are proteins that are present throughout the body, each with a unique function. Enzymes help to speed up (catalyze) routine and
vital chemical reactions in the body.
Among the most sensitive and widely used liver enzymes are the
aminotransferases. They include aspartate aminotransferase (AST or SGOT) and
alanine aminotransferase (ALT or SGPT). These enzymes are normally predominantly contained
within liver cells and to a lesser degree in the muscle cells. If the liver is injured or damaged, the liver cells spill
these enzymes into the blood, raising the AST and ALT enzyme blood levels and
signaling liver disease.
Other blood tests pertaining to the liver are measurements of some of the other enzymes found the liver. In addition to AST and ALT,
alkaline phosphatase, 5' nucleotidase, and gamma-glutamyl transpeptidase (GGT) are
a few of the other enzymes located in the liver. The focus of this article is mainly on the most common liver enzymes, AST and ALT.
Medical Author: Leslie J. Schoenfield, M.D., Ph.D. Medical Editor: Jay W. Marks, M.D.
The liver is the largest solid organ in the body. I think a lot of people
probably know that. But they may not know that it is also the largest gland in
the body. You see, the liver is also considered a gland because, among its
various functions, it makes and secretes bile. (Just for your reference, the
stomach and intestine are large hollow organs. Glands are organs or parts of
organs that make and secrete substances. And bile is a fluid that both aids in
digestion and transports fats as well as waste products into the intestine.)