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Physiology

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Endocrinology

Question
44 out of 50
 

Premenopausal peripheral conversion of estrogen precursors in the obese patient results in the formation of



A Estriol
B Estradiol

C Estrone
D Androstenedione

Ans. C Estrone

I. Androstenedione (also known as 4-androstenedione and 17-ketoestosterone) is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogensestrone and estradiol.

II. Aromatase is localized in the endoplasmic reticulum where it is regulated by tissue-specific promoters that are in turn controlled by hormones, cytokines, and other factors.

III. It catalyzes the last steps of estrogen biosynthesis from androgens (specifically, it transforms androstenedione to estrone and testosterone to estradiol).

IV. These steps include three successive hydroxylations of the 19-methyl group of androgens, followed by simultaneous elimination of the methyl group as formate and aromatization of the A-ring.

V. During the reproductive years, most estradiol(main form of estrogen) in women is produced by the granulosa cells of the ovaries by the aromatization of androstenedione (produced in the theca folliculi cells) to estrone, followed by conversion of estrone to estradiol by 17β-hydroxysteroid dehydrogenase.

Endocrinology Flashcard List

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