American Board of Pathology (ABPath) Practice Test

Thyroid-stimulating hormone (TSH) is produced by the pituitary gland, specifically by the anterior pituitary cells. TSH plays a critical role in regulating the thyroid gland's function, stimulating it to produce thyroid hormones (T3 and T4), which are essential for metabolic processes in the body. The release of TSH is regulated by thyrotropin-releasing hormone (TRH) from the hypothalamus, completing a feedback loop that maintains proper hormone levels and metabolic rates.

The thyroid gland, while crucial in producing thyroid hormones, does not produce TSH itself. The adrenal cortex is involved in the production of steroid hormones such as cortisol and aldosterone, and the pancreatic islets are responsible for producing insulin and glucagon, hormones that regulate blood sugar. Therefore, the correct identification of TSH's origin lies with the pituitary gland, which is responsible for triggering the thyroid's hormone production.