Q.95 Some endocrine glands produce hormones that stimulate functions of other endocrine glands.
Which ONE of the following hormones specifically acts to increase secretion of other hormones?
(A) Thyroxine (B) Prolactin (C) ACTH (D) ADH

ACTH: The Hormone That Triggers Other Endocrine Glands 

Some endocrine glands release tropic hormones to regulate others. ACTH is the key example among the options.

Correct Answer

(C) ACTH

Adrenocorticotropic hormone (ACTH), secreted by the anterior pituitary, specifically stimulates the adrenal cortex to produce glucocorticoids like cortisol and androgens. This tropic action fits the question perfectly, as it directly boosts hormone secretion from another gland.

Option Breakdown

Thyroxine (A)

Thyroxine (T4), produced by the thyroid gland, mainly regulates metabolism, growth, and development. It does not stimulate other endocrine glands to secrete hormones.​

Prolactin (B)

Prolactin from the anterior pituitary promotes lactation in mammary glands after childbirth. While it has minor effects elsewhere, it does not primarily trigger hormone secretion from other endocrine glands.​

ACTH (C)

As noted, ACTH binds to receptors on adrenal cortex cells, activating cAMP pathways to enhance steroidogenesis and cortisol release. This confirms its role as a classic tropic hormone.

ADH (D)

Antidiuretic hormone (ADH, or vasopressin) from the posterior pituitary controls water reabsorption in kidneys via aquaporins. It acts on renal tubules, not endocrine glands for hormone production.​

Why Tropic Hormones Matter

Tropic hormones like ACTH form the hypothalamic-pituitary axis, ensuring coordinated endocrine responses to stress. In exams like NEET, focus on pituitary hormones (TSH, FSH, LH, ACTH) as primary stimulators.​