SERUM GLUTAMIC PYRUVIC TRANSAMINASE (SGPT) (ALT)
SGPT is primarily a liver function test. It has a maximum concentration in the liver (fatty membranes) sinusoids. Low concentrations of SGPT are also found in the kidneys, heart, and skeletal muscle.
In pathological states, elevations indicate liver disease.
ALT is found in serum and in various bodily tissues but is most commonly associated with the liver. It catalyzes the transfer of an amino group from alanine to alpha-ketoglutarate, and the products of this reversible transamination reaction being pyruvate and glutamate.
glutamate + pyruvate ⇌ alpha-ketoglutarate + alanine
Alanine transaminase delivers skeletal muscle carbon and nitrogen in the form of alanine to the liver.
In skeletal muscle, pyruvate is transaminated to alanine, thus affording an additional route of nitrogen transport from muscle to liver. In the liver, alanine transaminase transfers the ammonia to A-KG and regenerates pyruvate. The pyruvate can then be diverted into gluconeogenesis. This process is referred to as the glucose-alanine cycle. The glucose-alanine cycle is used primarily as a mechanism for skeletal muscle to eliminate nitrogen as the muscles replenish their energy supply. Within the liver, alanine is converted back to pyruvate and is then a source of carbon atoms for gluconeogenesis. The newly formed glucose can then enter the bloodstream for delivery back to the muscle. The amino group transported from the muscle to the liver, in the form of alanine, is converted to urea in the urea cycle and then excreted.
In physiological states SGPT is a primary kreb cycle expressant and as a result causes the release of catabolic fats. SGPT occurs in serum as a consequence of substances being released by the fatty membranes of the liver sinusoids, and lymphatic ducts. The liver sinusoids store food, and the lymphatic ducts house toxins.
Picture a layer of fat that holds foods or toxins in the cell. Now as that layer of fat is being burned off, foods and toxins are being released in a controlled manner. This allows foods or toxins to be directed to their next destination.
Please note that most lab ranges for this test start at 0, which in actuality is false since this is a measurement of liver function, and 0 would mean that the liver was not functioning at all. A low range then should be around 15.
Therefore, from a physiological perspective, a low SGPT between 15-20 would indicate a sluggish liver causing many metabolic disturbances.
Typically these people have no energy, get sick a lot, cannot tolerate food well and have a slow metabolism.