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Rim Halaby (talk | contribs) Created page with "{{WBRQuestion |QuestionAuthor={{Rim}} |ExamType=USMLE Step 1 |Prompt=Androstenedione is an androgen formed by theca cells and transported to granulosa cells. It is converted t..." |
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|Prompt=Androstenedione is an androgen formed by theca cells and transported to granulosa cells. It is converted to estrogen by the action of enzyme X under the positive hormonal effect of follicle-stimulating hormone (FSH). FSH has time and dose-dependent activity on enzyme X. The illustration shown below demonstrates the enzymatic conversion of androstenedione to estrogen. Pharmacologic inhibition of enzyme X is most likely prescribed in which pathological condition? | |Prompt=Androstenedione is an androgen formed by theca cells and transported to granulosa cells. It is converted to estrogen by the action of enzyme X under the positive hormonal effect of follicle-stimulating hormone (FSH). FSH has time and dose-dependent activity on enzyme X. The illustration shown below demonstrates the enzymatic conversion of androstenedione to estrogen. Pharmacologic inhibition of enzyme X is most likely prescribed in which pathological condition? | ||
[[Image:WBR0339. | [[Image:WBR0339.png|500px]] | ||
|Explanation=Enzyme X described above is aromatase. FSH has a time- and dose-dependent mechanism for activation of aromatase. The enzyme is responsible for the conversion of androstenedione in granulosa cell to estrogen. Inhibition of aromatase by pharmacologic therapy (aromatase inhibitors), such as anastrozole and exemestane, is particularly beneficial in post-menopausal women with breast cancer. In these patients, inhibition of peripheral estrogen production is key for targeted therapy. | |Explanation=Enzyme X described above is aromatase. FSH has a time- and dose-dependent mechanism for activation of aromatase. The enzyme is responsible for the conversion of androstenedione in granulosa cell to estrogen. Inhibition of aromatase by pharmacologic therapy (aromatase inhibitors), such as anastrozole and exemestane, is particularly beneficial in post-menopausal women with breast cancer. In these patients, inhibition of peripheral estrogen production is key for targeted therapy. | ||
Revision as of 07:35, 21 November 2013
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | |
| Sub Category | |
| Prompt | [[Prompt::Androstenedione is an androgen formed by theca cells and transported to granulosa cells. It is converted to estrogen by the action of enzyme X under the positive hormonal effect of follicle-stimulating hormone (FSH). FSH has time and dose-dependent activity on enzyme X. The illustration shown below demonstrates the enzymatic conversion of androstenedione to estrogen. Pharmacologic inhibition of enzyme X is most likely prescribed in which pathological condition?
|
| Answer A | AnswerA::Benign prostate hyperplasia (BPH) |
| Answer A Explanation | AnswerAExp::Patients with BPH are prescribed alpha-1-antagonists, such as tamsulosin, or 5-alpha-reductase inhibitors, such as finasteride |
| Answer B | AnswerB::Prostate adenocarcinoma |
| Answer B Explanation | AnswerBExp::Anti-androgens such as flutamide are prescribed in prostate adenocarcinoma. |
| Answer C | AnswerC::Breast cancer in post-menopausal women |
| Answer C Explanation | AnswerCExp::Aromatase inhibitors are prescribed for breast cancer in post-menopausal women to decrease the peripheral production of estrogen. |
| Answer D | AnswerD::Contraception |
| Answer D Explanation | AnswerDExp::Hormone replacement therapy, such as progestin and estrogen, may be used for contraception. |
| Answer E | AnswerE::Triple negative breast cancer |
| Answer E Explanation | [[AnswerEExp::Patients with triple negative breast cancer, defined as breast cancers that do not express estrogen receptors (ER), progesterone receptors (PR), or Her2/neu, do not benefit from hormonal therapy, such as selective estrogen receptor modulators (SERMs) or aromatase inhibitors. Triple negative breast cancers are difficult to treat due to absence of specific targets for therapy.]] |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation::Enzyme X described above is aromatase. FSH has a time- and dose-dependent mechanism for activation of aromatase. The enzyme is responsible for the conversion of androstenedione in granulosa cell to estrogen. Inhibition of aromatase by pharmacologic therapy (aromatase inhibitors), such as anastrozole and exemestane, is particularly beneficial in post-menopausal women with breast cancer. In these patients, inhibition of peripheral estrogen production is key for targeted therapy.
Educational Objective:
Aromatase is an enzyme stimulated by FSH and is responsible for the conversion of androstenedione to estrogen. Aromatase inhibitors, such as anastrozole and exemestane are clinically useful in post-menopausal women with breast cancer. |
| Approved | Approved::No |
| Keyword | WBRKeyword::aromatase, WBRKeyword::inhibitor, WBRKeyword::inhibition, WBRKeyword::anastrozole, WBRKeyword::exemestane, WBRKeyword::postmenopausal, WBRKeyword::post-menopausal, WBRKeyword::post, WBRKeyword::menopausal, WBRKeyword::menopause, WBRKeyword::breast, WBRKeyword::cancer, WBRKeyword::estrogen, WBRKeyword::androstenedione, WBRKeyword::receptor, WBRKeyword::granulosa, WBRKeyword::cell, WBRKeyword::peripheral, WBRKeyword::conversion, WBRKeyword::FSH, WBRKeyword::follicle, WBRKeyword::stimulating, WBRKeyword::hormone |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
