WBR0510
| Author | [[PageAuthor::Gonzalo A. Romero, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pharmacology, MainCategory::Physiology |
| Sub Category | SubCategory::Endocrine, SubCategory::Reproductive |
| Prompt | [[Prompt::A pharmacist is planning a study with mice in order to determine the effects of a novel drug called “Pharma-WBR”. He knows that the drug is supposed to work in the hypothalamus, to regulate the release of different pituitary hormones. He measures serum concentration and determines that the drug causes different changes in FSH and LH if used continuously or pulsatile. He finds analogy of a drug existing in the market. Which of the following drugs has a similar mechanism of action as “Pharma-WBR”?]] |
| Answer A | AnswerA::Flutamide |
| Answer A Explanation | [[AnswerAExp::Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor used in prostate cancer.]] |
| Answer B | AnswerB::Finasteride |
| Answer B Explanation | [[AnswerBExp::Finasteride is a 5 alfa-reductase inhibitor used to treat BPH and male-pattern baldness.]] |
| Answer C | AnswerC::Mifepristone |
| Answer C Explanation | [[AnswerCExp::Mifepristone is a competitive inhibitor of progestins at the progesterone receptors. It is used to terminate pregnancy in combination with misoprostol (PGE1 analog).]] |
| Answer D | AnswerD::Ketoconazol |
| Answer D Explanation | [[AnswerDExp::Ketoconazol is a steroid synthesis inhibitor by inhibiting desmolase, which transforms cholesterol into pregnenolone.]] |
| Answer E | AnswerE::Leuprolide |
| Answer E Explanation | AnswerEExp::See overall explanation. |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::Leuprolide is a GnRH analog. If used in pulsatile fashion, it acts as an agonist, while if used continuously, it acts as an antagonist, because it downregulates the GnRH receptor in pituitary, therefore decreasing FSH and LH. It is often used continuously with flutamide to treat prostatic cancer or uterine fibroids. Leuprolide is often used pulsatile in cases of infertility. Educational Objective: # Leuprolide is a GrRH analog, which acts on the pituitary.
 References: First Aid 2012 for Step 1, Reproductive-Pharmacology chapter.]] |
| Approved | Approved::No |
| Keyword | WBRKeyword::Pituitary hormones |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |