In hypopituitarism, which anterior pituitary hormone is typically decreased?

• A. ADH
• B. Oxytocin
• C. TSH
• D. Melanocyte-stimulating hormone

Answer: (C)

Hypopituitarism means the anterior pituitary isn’t secreting its hormones adequately. Thyroid-stimulating hormone is a classic example of an anterior pituitary hormone that falls with pituitary failure, so its decrease directly explains secondary hypothyroidism: the thyroid is under-stimulated despite normal hypothalamic signals. The other hormones listed aren’t the anterior pituitary’s main players in this scenario: ADH and oxytocin come from the posterior pituitary and are released under hypothalamic control, not from the anterior lobe. Melanocyte-stimulating hormone is a minor product and not a primary diagnostic marker of anterior pituitary failure. Thus, TSH is the best answer because it directly reflects anterior pituitary dysfunction.