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Hormonal Regulation of Fuel Metabolism:- Cortisol Signals Stress, Including Low Blood Glucose

المؤلف:  David L. Nelson، Michael M. Cox

المصدر:  Lehninger Principles of Biochemistry

الجزء والصفحة:  909

2026-07-14

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Hormonal Regulation of Fuel Metabolism:- Cortisol Signals Stress, Including Low Blood Glucose

A variety of stressors (anxiety, fear, pain, hemorrhage, infections, low blood glucose, starvation) stimulate re lease of the corticosteroid hormone cortisol from the adrenal cortex. Cortisol acts on muscle, liver, and adipose tissue to supply the organism with fuel to with stand the stress. Cortisol is a relatively slow-acting hormone that alters metabolism by changing the kinds and amounts of certain enzymes synthesized in its target cell, rather than by regulating the activity of existing en zyme molecules. In adipose tissue, cortisol leads to an increase in the release of fatty acids from stored TAGs. The fatty acids are exported to serve as fuel for other tissues, and the glycerol is used for gluconeogenesis in the liver. Corti sol stimulates the breakdown of muscle proteins and the export of amino acids to the liver, where they serve as precursors for gluconeogenesis. In the liver, cortisol promotes gluconeogenesis by stimulating synthesis of the key enzyme PEP carboxykinase glucagon has the same effect, whereas insulin has the opposite effect. Glucose produced in this way is stored in the liver as glycogen or exported immediately to tis sues that need glucose for fuel. The net effect of these metabolic changes is to restore blood glucose to its nor mal level and to increase glycogen stores, ready to support the fight-or-flight response commonly associated with stress. The effects of cortisol therefore counter balance those of insulin.