Cortisone is a glucocorticoid-related steroid hormone that functions primarily as an inactive or less active counterpart to cortisol. Its biological importance lies in regulation of local glucocorticoid availability within tissues. By converting active cortisol into cortisone, tissues can reduce glucocorticoid receptor activation and limit excessive cortisol signaling. Conversely, cortisone can be converted back into active cortisol in tissues requiring increased glucocorticoid activity.
This reversible cortisol-cortisone system allows fine regulation of glucocorticoid exposure in liver, kidney, adipose tissue, brain, vascular tissue, and additional organs. Through these mechanisms, cortisone indirectly influences metabolism, inflammatory signaling, electrolyte balance, vascular responsiveness, stress adaptation, and tissue-specific endocrine regulation.
Cortisone is produced mainly through enzymatic conversion of cortisol by 11-beta-hydroxysteroid dehydrogenase type 2. This enzyme is highly expressed in mineralocorticoid-sensitive tissues such as kidney, colon, salivary glands, and placenta. Conversion of cortisol into cortisone prevents excessive activation of mineralocorticoid receptors by glucocorticoids and preserves selective aldosterone signaling.
Cortisone can also be reconverted into cortisol through activity of 11-beta-hydroxysteroid dehydrogenase type 1, which is abundant in liver, adipose tissue, skeletal muscle, and central nervous system tissues. This bidirectional conversion system creates localized endocrine control over glucocorticoid exposure without requiring large fluctuations in adrenal cortisol secretion.
Cortisone levels are regulated by adrenal cortisol production, tissue-specific enzyme expression, circadian rhythm signaling, stress pathways, inflammatory mediators, nutritional state, thyroid hormone interactions, and liver-kidney metabolic function. Activity of 11-beta-hydroxysteroid dehydrogenase enzymes determines whether tissues favor glucocorticoid activation or inactivation.
Inflammatory cytokines, oxidative stress, metabolic signaling, and nutrient-related pathways can alter enzyme expression patterns and thereby influence local cortisol-cortisone balance. Cortisone itself has relatively weak direct glucocorticoid receptor activity until converted back into cortisol. Its major endocrine role is therefore modulation of tissue glucocorticoid exposure. Through this regulatory system, cortisone helps maintain balanced glucocorticoid signaling across organs with differing metabolic, vascular, and electrolyte-regulating requirements.
Cortisone is the inactive partner of cortisol, enabling tissue-specific control of glucocorticoid action through the 11β-HSD shuttle.
