Which of the following hormones inhibits release of growth hormone?

AIIMS Patna NO - 2020

Applied Physiology

Easy

Appeared in: AIIMS Patna NO - 2020

Explanation

Somatostatin, also known as Growth Hormone-Inhibiting Hormone (GHIH), is a peptide hormone produced in the hypothalamus.
It is released into the hypothalamic-pituitary portal system and travels to the anterior pituitary gland.
At the anterior pituitary, somatostatin binds to receptors on somatotrope cells, directly inhibiting the synthesis and secretion of growth hormone (somatotropin).
The regulation of growth hormone secretion is balanced by the opposing actions of stimulatory GHRH (Growth Hormone-Releasing Hormone) and inhibitory Somatostatin.

Option A: Dopamine's primary inhibitory role in the hypothalamus-pituitary axis is on prolactin secretion, not growth hormone. It is also known as Prolactin-Inhibiting Factor (PIF).
Option B: Somatotropin is another name for Growth Hormone (GH) itself. It is the hormone that is being regulated, not the hormone that inhibits its own release.
Option D: Thyrotropin-inhibiting hormone is not a standard or distinct hormonal name. The hormone that inhibits the release of thyrotropin (TSH) is actually somatostatin, which also inhibits growth hormone.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormonal Regulation of Growth Hormone as background academic context rather than a clinical decision trigger.
Understanding the inhibitory role of somatostatin is critical for comprehending the pathophysiology of conditions like acromegaly (GH excess), which can be caused by pituitary tumors.
Synthetic analogs of somatostatin, such as octreotide and lanreotide, are cornerstone pharmacologic treatments for acromegaly. Nurses administering these medications must understand their mechanism of action to monitor for efficacy and side effects (e.g., gastrointestinal upset, gallstones).
What if? If a patient has a tumor that secretes GHRH ectopically (e.g., a lung carcinoid tumor), the resulting clinical picture would be acromegaly due to excessive stimulation of GH release, overriding the normal inhibitory control by somatostatin.

How to Approach the Question

First, identify the key concept in the question: the inhibition of growth hormone release.
Recall the hypothalamic-pituitary axis for growth hormone. Remember that the hypothalamus produces both a releasing hormone (GHRH) and an inhibiting hormone.
Systematically evaluate each option. Ask yourself, 'What is the primary function of this hormone?'
Eliminate 'Somatotropin' first, as it is another name for growth hormone itself.
Recall that Dopamine's main inhibitory role is on prolactin.
This leaves Somatostatin. Recognize its alternative name, Growth Hormone-Inhibiting Hormone (GHIH), which makes it the most logical answer.

Concept Tested & Keywords

QSiBCP_OOsmyrJ8pHR2uYb

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart B (pp 240-463 of 478) p. 141-143

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1163-1165

E6 Physiology Ganong 27e Vol 1 Part 2 p. 105-107