BRAIN METABOLISM

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 The brain is one of the most metabolically active organs in the body accounting for up to 20% of the body's total energy at rest The heart and kidneys are more metabolically active than the b... rain, but as the brain is larger, thus takes a higher proportion of the body’s energy needs. Glucose is virtually the sole fuel for the human brain, except during prolonged starvation where ketone bodies serve as the source of fuel for the brain. The brain consumes about 120 g daily of glucose. Energy requirements is not uniform throughout the brain but is increased in localized regions dependent on neuronal activity. Metabolic Patterns of the Brain2 The bulk of the brain’s energy (80%), is used to power transport mechanisms that maintain the Na+/K+ membrane potential required for the transmission of the nerve impulses. The remaining energy is used for cell-health maintenance / resting potential of neurons. The brain stores little energy as glycogen and relies almost entirely on circulating glucose for fuel. Once inside the neurons, glucose is metabolized by mitochondria to produce cellular energy (ATP). Glucose is transported into brain cells by the glucose transporter 3 (GLUT3). [Show More]

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