TSH feedback refers to the regulatory mechanism by which circulating thyroid hormones (T3 and T4) inhibit the secretion of thyroid-stimulating hormone (TSH) from the anterior pituitary gland, maintaining hormonal balance. This negative feedback loop is crucial for diagnosing and managing thyroid disorders, as abnormal TSH levels often indicate hypo- or hyperthyroidism. For example, elevated TSH with low thyroid hormones suggests primary hypothyroidism, guiding appropriate treatment decisions.