Lipid metabolism: prostaglandin E1 and the ductus arteriosus: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Biochemistry · Lipid metabolism: prostaglandin E1 and the ductus arteriosus

Sample item

A newborn with critical pulmonary atresia is cyanosed at 2 days of age as the ductus arteriosus begins to close. An infusion is started to keep the vessel open. Which eicosanoid does the drug mimic?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Prostaglandin E1

Prostaglandin E1 (alprostadil) relaxes ductal smooth muscle and maintains patency in duct-dependent circulations until surgery. Indomethacin does the reverse by inhibiting prostaglandin synthesis to close a patent duct.

Option by option

  • A. Thromboxane A2

    Thromboxane A2 causes vasoconstriction and platelet aggregation, which would not keep the duct open.

  • B. Leukotriene D4

    Leukotriene D4 causes bronchoconstriction and has no role in ductal patency.

  • C. Prostaglandin E1 (correct)

    Correct. Alprostadil, a prostaglandin E1 preparation, keeps the ductus arteriosus open.

  • D. Prostaglandin F2 alpha

    Prostaglandin F2 alpha stimulates uterine contraction and does not relax the ductus.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is C, Prostaglandin E1. Prostaglandin E1 (alprostadil) relaxes ductal smooth muscle and maintains patency in duct-dependent circulations until surgery.

Why is "Thromboxane A2" not the answer?

Thromboxane A2 causes vasoconstriction and platelet aggregation, which would not keep the duct open.

Why is "Leukotriene D4" not the answer?

Leukotriene D4 causes bronchoconstriction and has no role in ductal patency.

Why is "Prostaglandin F2 alpha" not the answer?

Prostaglandin F2 alpha stimulates uterine contraction and does not relax the ductus.

What concept does this question test?

It tests Lipid metabolism: prostaglandin E1 and the ductus arteriosus in Biochemistry. Indomethacin does the reverse by inhibiting prostaglandin synthesis to close a patent duct.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Lipid metabolism: prostaglandin E1 and the ductus arteriosus?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.