A bodybuilder self-administering high-dose testosterone develops bilateral gynaecomastia. Which androgenic compound could theoretically provide anabolic effects without this complication because it cannot undergo the responsible metabolic step?
- A Testosterone enanthate
- B Methyltestosterone
- C Dihydrotestosterone ✓
- D Nandrolone
Correct answer: C. Dihydrotestosterone
Explanation
Gynaecomastia arises when the aromatase enzyme converts testosterone and its 19-carbon analogues into oestradiol in peripheral tissues such as adipose. Dihydrotestosterone is already 5 alpha-reduced and is not a substrate for aromatase, so it generates no oestrogen and cannot cause gynaecomastia by this route. Testosterone enanthate, methyltestosterone and nandrolone all retain the aromatisable A ring and can produce oestrogenic effects. This aromatisation principle also explains why aromatase inhibitors are misused alongside steroids.
Reference: Katzung Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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