Ketone body formation takes place in?

NHM UP Staff Nurse - 2017

Biochemistry & Nutrition

Easy

Appeared in: NHM UP Staff Nurse - 2017

Explanation

Ketogenesis, the synthesis of ketone bodies, occurs almost exclusively in the mitochondria of liver cells (hepatocytes).
During states of high fatty acid oxidation, such as fasting or uncontrolled diabetes, the liver converts excess acetyl-CoA into acetoacetate, 3-hydroxybutyrate, and acetone.
The liver is a net exporter of ketone bodies because it lacks the enzyme thiophorase, which is required for their utilization, making them available for other tissues.
These water-soluble compounds are then transported via the blood to serve as a vital energy source for extrahepatic tissues like the brain, heart, and muscles.

Option B: The kidney is a site of ketone body utilization, not synthesis. The cells of the renal cortex can take up ketone bodies from the blood and use them for energy.
Option C: The spleen's primary functions are related to filtering blood and mounting immune responses. It is not involved in major metabolic pathways like ketogenesis.
Option D: Blood is the medium for transporting substances throughout the body. It carries ketone bodies from the liver to peripheral tissues but does not produce them.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Site of ketone body formation (ketogenesis) as background academic context rather than a clinical decision trigger.
Understanding ketogenesis is critical for managing Diabetic Ketoacidosis (DKA), a life-threatening complication of uncontrolled diabetes where excessive ketone production causes severe metabolic acidosis.
Nurses monitor for ketosis (elevated ketones in blood and urine) in at-risk patients, such as those with Type 1 diabetes, prolonged starvation, or on ketogenic diets. A characteristic 'fruity' or acetone-like smell on a patient's breath is a key clinical sign.
In a hospital setting, urine dipstick tests (Rothera's test) or point-of-care blood tests are used to quickly assess for the presence and level of ketones.

How to Approach the Question

First, identify the key physiological process in the question: 'Ketone body formation,' which is also known as ketogenesis.
Next, consider the primary metabolic functions of the organs listed in the options.
Recall that the liver is the central metabolic organ in the body, responsible for processing nutrients and synthesizing molecules for use by other tissues.
Contrast this with the other options: the kidney's main role is filtration and excretion, the spleen's is immunological, and blood's is transport.
Conclude that the synthesis of a major energy substrate like ketone bodies is a function of the liver.
Eliminate the other options based on their primary physiological roles, which do not include large-scale metabolic synthesis for export.

Concept Tested & Keywords

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E6 Harper's Illustrated Biochemistry2023 (pp 26-793 of 813) p. 205-207

E6 Biochemistry U Satyanarayana— Part 1 (pp 26-420 of 840) p. 286-288

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 1 (pp 26-370 of 370) p. 236-238