The metabolic patterns of the brain, muscle, adipose tissue, kidney, and liver are strikingly different. Let us consider how these organs differ in their use of fuels to meet their energy needs:

1. Brain. Glucose is virtually the sole fuel for the human brain, except during prolonged starvation.

2. Muscle. The major fuels for muscle are glucose, fatty acids, and ketone bodies

3. Adipose tissue. The triacylglycerols stored in adipose tissue are an enormous reservoir of metabolic fuel

4. The kidney. The major purpose of the kidney is to produce urine

5. Liver. The metabolic activities of the liver are essential for providing fuel to the brain, muscle, and other peripheral

Berg JM, Tymoczko J, Stryer L. Biochemistry. 5th edition. New York, NY: W. H., and Freeman; 2002. Section 30.2, Each Organ Has a Unique Metabolic Profile; (2002). Available online at:  [Google Scholar]