Physiology · Reproductive Physiology

Aromatase (CYP19A1) is essential for estrogen biosynthesis. Which substrate does aromatase convert to estradiol in the ovary?

A Testosterone ✓
B Progesterone
C Androstenedione
D Dihydrotestosterone

Correct answer: A. Testosterone

Explanation

Aromatase converts testosterone to estradiol in granulosa cells. Androstenedione is converted to estrone (a weaker estrogen), not estradiol. This specificity is clinically relevant because aromatase inhibitors (letrozole) are used for ovulation induction and estrogen receptor-positive breast cancer.

Reference: Ganong's Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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