CHAPTER 37: GLUCONEOGENESIS

The process in the liver and kidneys by which noncarbohydrate substrates are converted to glucose 6-phosphate, providing glucose as an energy substrate for various cell types.

Gluconeogenesis

Amino acids that are converted to glucose during gluconeogenesis, contributing to the production of glucose in the liver.

Glucogenic Amino Acids

A source of glucose during exercise and concentrated carbohydrate feeding, which can be converted to glucose through the lactic acid cycle.

Lactate

A waste product of lipolysis that is converted to glucose in the liver, serving as a significant source of glucose in hibernating animals.

Glycerol

A volatile fatty acid produced from microbial carbohydrate digestion in ruminants and herbivores, serving as a major hepatic gluconeogenic substrate.

Propionate

Enzymes involved in the pathway of gluconeogenesis, including pyruvate carboxylase, PEP carboxykinase, fructose 1,6-bisphosphatase, glucose 6-phosphatase, and glycerol kinase.

Gluconeogenic Enzymes

A mitochondrial enzyme activated by acetyl-CoA, converting pyruvate to oxaloacetate, allowing for the production of glucose in gluconeogenesis.

Pyruvate Carboxylase

An enzyme that catalyzes the conversion of oxaloacetate to phosphoenolpyruvate (PEP) in the cytoplasm, a key step in gluconeogenesis.

PEP Carboxykinase

An inducible enzyme that bypasses the regulatory step of glycolysis, allowing for the production of glucose in gluconeogenesis.

Fructose 1,6-Bisphosphatase

An enzyme present in the liver and kidney tissue that removes phosphate from glucose 6-phosphate, enabling glucose to be released into the blood.

Glucose 6-Phosphatase