Which hormone is odd one?

Appeared in: BSF Staff Nurse - 2021

Explanation

ADR (Adrenaline) is the correct answer as it is chemically different from the other options.
ADR is an amine hormone, specifically a catecholamine, derived from the amino acid tyrosine.
The other three hormones—Corticotrophin (ACTH), Vasopressin (ADH), and Prolactin—are all peptide or protein hormones.
Additionally, ADR is secreted by the adrenal medulla, whereas the other three are secreted by the pituitary gland (anterior or posterior).

Option A: Corticotrophin (ACTH) is a polypeptide hormone secreted by the anterior pituitary, similar in chemical nature (peptide) and general origin (pituitary) to Vasopressin and Prolactin.
Option C: Vasopressin (ADH) is a peptide hormone secreted by the posterior pituitary. It shares its peptide nature with Corticotrophin and Prolactin.
Option D: Prolactin is a protein hormone secreted by the anterior pituitary. It fits with the group of pituitary-derived peptide/protein hormones.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hormone Classification as background academic context rather than a clinical decision trigger.
Understanding hormone classification is crucial for pharmacology. For instance, peptide hormones (like insulin, ACTH) are digested if taken orally and must be injected, whereas some steroid and amine hormones can be administered orally.
Diagnostic tests for endocrine disorders often involve measuring hormone levels. Knowing the origin gland helps pinpoint the location of a potential tumor or dysfunction (e.g., high ACTH suggests a pituitary issue).
What if? - If the options were Cortisol, Aldosterone, Testosterone, and Adrenaline, the odd one out would still be Adrenaline. The first three are steroid hormones, while Adrenaline is an amine hormone.

How to Approach the Question

First, identify the core task of the question, which is to find the 'odd one out'.
Analyze the given options: Corticotrophin, ADR, Vasopressin, Prolactin. Recognize these are all hormones.
Think of different ways to classify these hormones. Common classification systems in biology are based on structure, function, or origin.
Recall or deduce the chemical nature of each hormone. Corticotrophin, Vasopressin, and Prolactin are peptides/proteins. ADR (Adrenaline) is an amine.
Recall or deduce the gland of origin for each. Corticotrophin, Vasopressin, and Prolactin are all from the pituitary gland. ADR is from the adrenal medulla.
Based on these two distinct differences (chemical nature and origin), conclude that ADR is the odd one out.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 2B p. 104-106

E6 Pharmacology Katzung 16e p. 1042-1044

E6 Biochemistry U Satyanarayana— Part 2 (pp 421-820 of 840) p. 56-58

Practise the full BSF Staff Nurse - 2021

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