Why does prolonged elevated cortisol due to chronic stress often impair thyroid function?

💡 Explanation

Cortisol excess affects the hypothalamic-pituitary-thyroid axis through negative feedback loops, because chronically elevated cortisol inhibits the secretion of both TSH (thyroid-stimulating hormone) and T4 (thyroxine). Therefore, thyroid hormone production decreases, rather than cortisol directly stimulating thyroxine or enhancing its receptor affinity.

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