GLUCONEOGENESIS

INTRODUCTION: Gluconeogenesis is a metabolic pathway that results in the generation of glucose from certain non-carbohydrate carbon substrates. From breakdown of proteins, these substrates include glucogenic amino acids. From breakdown of lipids such as triglycerides, they include glycerol. From other steps in metabolism they include pyruvate and lactate. PYRUVATE LACTATE 

ROLE OF GLUCONEOGENESIS:  Gluconeogenesis is one of several main mechanisms used by humans and many other animals to maintain blood glucose levels, avoiding low levels also known as hypoglycemia. Other means include the degradation of glycogen also known as glycogenolysis, and fatty acid breakdown.

SITES OF GLUCONEOGENESIS:  Gluconeogenesis is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In vertebrates, gluconeogenesis takes place mainly in the liver and, to a lesser extent, in the cortex of the kidneys. In many other animals, the process occurs during periods of fasting, starvation, low-carbohydrate diets, or intense exercise. 

The process is highly endergonic until it is coupled to the hydrolysis of ATP or GTP, effectively making the process exergonic. For example, the pathway leading from pyruvate to glucose-6-phosphate requires 4 molecules of ATP and 2 molecules of GTP to proceed spontaneously. Gluconeogenesis is often associated with ketosis. Gluconeogenesis is also a target of therapy for type 2 diabetes, such as the antidiabetic drug, metformin, which inhibits glucose formation and stimulates glucose uptake by cells.  In ruminants, because metabolizable dietary carbohydrates tend to be metabolized by rumen organisms, gluconeogenesis occurs regardless of fasting, low-carbohydrate diets, exercise, and many others.

RELATED;

1.  GLYCOLYSIS

2.  GLYCOGEN

3.  BIOCHEMISTRY

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