All of the following are hormones of the adrenal medulla, EXCEPT:

Appeared in: DSSSB 12 August 2024

Explanation

Serotonin is the correct answer as it is not a hormone produced by the adrenal medulla.
It is classified as a monoamine neurotransmitter, specifically an indolamine, which is synthesized from the amino acid tryptophan.
The vast majority of serotonin is found in the gastrointestinal (GI) tract, with smaller amounts in the central nervous system (CNS) and blood platelets.

Option B: This is incorrect because Adrenaline (epinephrine) is the primary hormone secreted by the adrenal medulla, accounting for approximately 80% of its catecholamine output.
Option C: This is incorrect because Dopamine is a catecholamine that is synthesized and secreted in small amounts by the adrenal medulla. It also serves as a precursor for noradrenaline and adrenaline.
Option D: This is incorrect because Noradrenaline (norepinephrine) is a major catecholamine hormone secreted by the adrenal medulla, making up about 20% of its output.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormones of the Adrenal Medulla as background academic context rather than a clinical decision trigger.
Understanding the hormones of the adrenal medulla is crucial for diagnosing pheochromocytoma, a tumor that secretes excess catecholamines, leading to severe hypertension, palpitations, and headaches.
Conversely, tumors that secrete excess serotonin are known as carcinoid tumors, which present with different symptoms like flushing, diarrhea, and wheezing (carcinoid syndrome).
What if? If a patient presented with episodic flushing and diarrhea, and lab tests showed elevated levels of 5-HIAA (a serotonin metabolite) in the urine, the focus would shift from the adrenal medulla to investigating a carcinoid tumor, not a pheochromocytoma.

How to Approach the Question

First, identify the core subject of the question, which is the hormones produced by the 'adrenal medulla'.
Note the keyword 'EXCEPT'. This means you are looking for the option that does NOT belong.
Recall the class of hormones secreted by the adrenal medulla: catecholamines.
Systematically review the options: Adrenaline, Noradrenaline, and Dopamine are all well-known catecholamines.
Identify Serotonin as the outlier. It is a different type of neurotransmitter (a monoamine, but not a catecholamine) synthesized from a different precursor (tryptophan, not tyrosine).
Therefore, Serotonin is the correct exception.

Concept Tested & Keywords

Concept Tested: Hormones of the Adrenal Medulla
Stem keywords: hormones, adrenal medulla
Lead-in keywords: EXCEPT
Negative lead-in flag: The question asks for the option that is NOT a hormone of the adrenal medulla.

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E6 Physiology Essentials Sembulingam 10e Part 2 pp. 84-86, 85-87

E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) p. 3011-3013

Practise the full DSSSB 12 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.