31 - Describe the biochemistry of the Cori cycle and the glucose–alanine cycle. How are they regulated and under what physiological conditions are they activated?
The Cori cycle and glucose-alanine cycle are two mechanisms that involve cycling of nutrients between the liver and muscle. Lactate and alanine are two glucogenic molecules that are each converted to pyruvate via a series of enzymatic reactions in the liver to ultimately be converted to glucose via gluconeogenesis and transported back to muscle for its energy source.
The Cori cycle describes the metabolic pathway in which the anaerobic glycolytic product in the muscle known as lactate, is transported to the liver where it gets converted back to glucose for it to be returned to the muscle (Overgaard et al., 2009). Simply put, the cycle integrates metabolism between muscle and liver through lactate. As liver plays a central role in maintaining blood glucose, this is one way liver talks to the muscle in our body.
When muscle cells are in need of energy, they acquire ATP as its source of energy from the mobilization of glycogen through a process known as glycogenolysis. Glucose-1-P …show more content…
Lactate passes through blood into the liver where it gets re-oxidized to pyruvate via the reversible enzymatic activity of lactate dehydrogenase. Gluconeogenesis stimulated by glucagon then allows for pyruvate to be converted to glucose, which subsequently gets transported back to the muscle for glycolysis or glycogen synthesis depending on its energy need. An important aspect of the cycle is that the compartmentalization of glycolysis to muscle and gluconeogenesis to liver allows for the two reactions to occur simultaneously. If these two metabolic processes were to happen within the same cell, futile cycle would
The Cori cycle and glucose-alanine cycle are two mechanisms that involve cycling of nutrients between the liver and muscle. Lactate and alanine are two glucogenic molecules that are each converted to pyruvate via a series of enzymatic reactions in the liver to ultimately be converted to glucose via gluconeogenesis and transported back to muscle for its energy source.
The Cori cycle describes the metabolic pathway in which the anaerobic glycolytic product in the muscle known as lactate, is transported to the liver where it gets converted back to glucose for it to be returned to the muscle (Overgaard et al., 2009). Simply put, the cycle integrates metabolism between muscle and liver through lactate. As liver plays a central role in maintaining blood glucose, this is one way liver talks to the muscle in our body.
When muscle cells are in need of energy, they acquire ATP as its source of energy from the mobilization of glycogen through a process known as glycogenolysis. Glucose-1-P …show more content…
Lactate passes through blood into the liver where it gets re-oxidized to pyruvate via the reversible enzymatic activity of lactate dehydrogenase. Gluconeogenesis stimulated by glucagon then allows for pyruvate to be converted to glucose, which subsequently gets transported back to the muscle for glycolysis or glycogen synthesis depending on its energy need. An important aspect of the cycle is that the compartmentalization of glycolysis to muscle and gluconeogenesis to liver allows for the two reactions to occur simultaneously. If these two metabolic processes were to happen within the same cell, futile cycle would