Metabolism III: Disruption

Question 1

Canine Blood Glucose Curve

Answer 1

Curve based on the assumption of meals in morning and evening.
• Normal blood glucose in the 100-250 mg/dl range.
• Blood glucose level drops between morning and evening meal.

Insulin secreted by the pancreas in response to a rise in blood glucose levels.
• Increases glucose (G-6-P) conversion to Glycogen in the liver.

Question 2

Canine Blood Glucose Curve: Diabetic Dog

Answer 2

Insufficient insulin production and release in response to a meal.
• Reduced Glucose storage as Glycogen.
• Increased blood glucose levels.

Question 3

Disruption of Carbohydrate Metabolism

Answer 3

Lack of reciprocal control over Glucagon results in unchecked hyperglycaemia.
• Liver effectively mimics ‘starved’ state.
• Glucose accumulates, fat metabolism increases resulting in increased ketone body generation (Ketogenesis).

Glucagon activity unchecked by lack of insulin.
• Glycogen rapidly broken down into G-6-P.
• G-6-P rapidly converted into Glucose and released into the blood stream.

HSL activity unchecked by lack of insulin.
• TAG rapidly metabolised into ketone bodies and fatty acids.
• Inhibited uptake of TAG and lipogenesis.

Question 4

Insulin Replacement

Answer 4

Careful dose control required in relation to meals and exercise.
• Risk of hypoglycaemic episodes (exercise and skipped meals).
• Monitoring of secondary complications.

Question 5

Amino Acid Metabolism:

Answer 5

Amino acids can be used as a source of energy.
• More prevalent during ‘starved states’
• Disruption of this pathway has significant consequences on energy production.
• Secondary impact on protein synthesis and availability.

Question 6

Disruption of AA Metabolism: Pyruvate Kinase Deficiency

Answer 6

Pyruvate dehydrogenase complex deficiency (PDCD) is a genetic disorder.
• Pyruvate dehydrogenase is the enzyme that X converts pyruvate into acetyl CoA, the molecule
necessary to begin the TCA cycle to produce ATP.
• With low levels of the pyruvate dehydrogenase complex (PDC), the rate of cycling through the TCA cycle is dramatically reduced.
• This results in a decrease in the total amount of energy that is produced by the cells of the body.

Question 7

Disruption of AA Metabolism: Phenylketonuria

Answer 7

Phenylalanine is an essential amino acid.
• Metabolised in Tyrosine by Phenylalanine hydroxylase.
• Downstream metabolic products include dopamine and melanin

• Phenylketonuria (PKU) is a genetic disorder.
• Lack sufficient activity of the enzyme phenylalanine hydroxylase.
• Unable to break down phenylalanine into tyrosine adequately.
• Levels of phenylalanine rise to toxic levels in the body.
• Results in damage to the central nervous system and brain.

Question 8

Fat Metabolism

Answer 8

Dietary fats are either used for:
• Energy production (liver and muscle)
• Storage (adipose tissue)
• Conversion (cholesterol, bile acids, steroids)

Question 9

Hyperlipidemia

Answer 9

Hyperlipidemia is a genetic disorder.
• The defect makes the body unable to remove low density lipoprotein (LDL)cholesterol from the blood.
• This results in a high level of LDL in the blood.