Gluconeogenesis Maintains Blood Glucose

Endocrine and Metabolism Block, MD Phase I 2010/2011

SLU: Endocrine and Metabolism - Discuss the role of gluconeogenesis in maintaining blood glucose level

Prepared by Dr Julia Omar, Assoc Prof Dr KNS Sirajudeen, Dr Win Mar Kyi, Dr Zulkarnain Mustapha, Dr Aini Suzana Adenan & Professor Faridah Abdul Rashid
27 & 28 February 2011

1. Discuss the role of gluconeogenesis in maintaining blood glucose level.

Reference:
Clinical Biochemistry for Medical Students, M.F. Laker (1996) - page 3

Gluconeogenesis

- Other compounds which are gluconeogenic substrates are also converted to glucose in the liver; lactate, glycerol and amino acids, particularly alanine (Ala).
- Lactate is continually produced by partial oxidation of glucose in muscle and erythrocytes and is reconverted to glucose in the liver by the Cori cycle.
- Alanine is formed in muscle by transamination of pyruvate (pyruvate is derived from glucose by partial glycolysis). The liver has a high capacity to extract alanine from blood.

Reference:
Clinical Chemistry in diagnosis and treatment, Philip D Mayne (1994) - page 200

Under normal aerobic conditions the liver can synthesize glucose by gluconeogenesis using the metabolic products from other tissues, such as glycerol, lactate or the carbon chains resulting from deamination of certain amino acids (mainly alanine) (Table 10.3)

Table 10.3: Metabolism of the carbon skeleton of some amino acids to either carbohydrate (glycogenic) or fat (ketogenic)

- Glycogenic: Ala, Arg, Gly, His, Met, Ser, Val

- Glycogenic & Ketogenic: Ile, Lys, Phe, Tyr

- Ketogenic: Leu