Biochemistry Question and overproduction of ketone bodies

Question

b) Briefly account for the overproduction of ketone bodies in diabetes mellitus and starvation. [5] 

Answer 1

1) In the case of starvation, gluconeogenesis will increase to account for a lack of glucose in the diet, therefore depleting citric acid cycle intermediates. This then causes acetyl-coA oxidation to slow down, and diverts acetyl-coA into ketone body formation instead.

2) In the case of diabetes mellitus, there is insufficient insulin present to help glucose be taken up by the tissues (other than the liver). A lack of glucose in the tissues causes gluconeogenesis to increase, causing blood glucose levels to elevate even further. Fatty acid oxidation in the liver and muscle accelerates so that the body can produce a fuel source that doesn't require insulin: ketone bodies. However, this production is faster than the rate at which the body can oxidize the ketone bodies, causing a buildup of ketones in the blood. The acidic ketone bodies cause blood pH to decrease, resulting in diabetic ketoacidosis.