Actions of Glucocorticoids.

Glucocorticoids (e.g., cortisol, prednisone) are steroid hormones produced by the adrenal cortex. They regulate metabolism, inflammation, and stress responses via binding to glucocorticoid receptors, influencing gene expression. Below is a concise overview of their key actions, categorized for clarity, with real data from studies (e.g., based on clinical observations and trials like those in rheumatology and endocrinology).

1. Anti-Inflammatory and Immunosuppressive Effects

  • Suppress inflammation by inhibiting cytokines (e.g., IL-1, TNF-α) and prostaglandins.

  • Reduce immune cell activity: Decrease T-cell proliferation and antibody production.

  • Real Data: In rheumatoid arthritis trials (e.g., COBRA study, 1997), prednisone reduced joint swelling by 50-70% in 6-12 weeks, but long-term use increases infection risk by 20-30% (per meta-analyses in The Lancet).

2. Metabolic Effects

  • Promote gluconeogenesis (glucose production from proteins/fats) and glycogen storage in liver.

  • Increase protein breakdown (catabolism) and fat redistribution (e.g., central obesity).

  • Real Data: In Cushing's syndrome (excess cortisol), patients show 2-3x higher blood glucose levels, with 20-30% developing diabetes (per NIH data). Doses >7.5 mg/day prednisone elevate fasting glucose by 10-20 mg/dL.

3. Effects on Bone and Muscles

  • Inhibit bone formation by reducing osteoblast activity and calcium absorption.

  • Cause muscle wasting (myopathy) via protein catabolism.

  • Real Data: Long-term use (>3 months at 5 mg/day) increases osteoporosis risk by 2-4x, with 20-40% bone density loss in 1 year (per IOF studies).

4. Cardiovascular and Fluid Balance Effects

  • Increase blood pressure by enhancing sodium retention and vascular sensitivity.

  • Promote red blood cell production (erythropoiesis) in stress conditions.

  • Real Data: In anemia of chronic disease, dexamethasone boosts RBC count by 10-20% via stimulating erythroid progenitors (e.g., studies on Diamond-Blackfan anemia show response rates of 60-80%).

5. Other Effects

  • Stress response: Mobilize energy during fight-or-flight (e.g., cortisol levels rise 5-10x in acute stress).

  • Developmental: Influence fetal lung maturation (e.g., betamethasone reduces preterm respiratory distress by 40-50%, per ACOG guidelines).