Reproduction: suckling and prolactin: practice question

A Physiology 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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Physiology · Reproduction: suckling and prolactin

Sample item

How does suckling cause a rapid rise in prolactin secretion?

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

The answer and the reasoning

C. Afferent nerve signals reduce hypothalamic dopamine release, releasing lactotrophs from inhibition

Suckling stimulates nipple receptors, and the neural signal reduces dopamine release from tuberoinfundibular neurons. As dopamine is the main prolactin-inhibiting factor, lactotrophs are disinhibited and prolactin rises, maintaining milk production.

Option by option

  • A. Circulating thyroxine stimulates lactotrophs

    Thyroxine does not mediate the suckling response.

  • B. Rising progesterone after delivery drives lactotrophs

    Progesterone falls after delivery and does not drive prolactin release.

  • C. Afferent nerve signals reduce hypothalamic dopamine release, releasing lactotrophs from inhibition (correct)

    Correct. A neural reflex lowers dopamine, and lactotrophs are released from inhibition.

  • D. Circulating oestrogen from milk stimulates lactotrophs

    Milk does not carry oestrogen that stimulates lactotrophs.

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 Physiology question

What is the answer to this Physiology question?

The best answer is C, Afferent nerve signals reduce hypothalamic dopamine release, releasing lactotrophs from inhibition. Suckling stimulates nipple receptors, and the neural signal reduces dopamine release from tuberoinfundibular neurons.

Why is "Circulating thyroxine stimulates lactotrophs" not the answer?

Thyroxine does not mediate the suckling response.

Why is "Rising progesterone after delivery drives lactotrophs" not the answer?

Progesterone falls after delivery and does not drive prolactin release.

Why is "Circulating oestrogen from milk stimulates lactotrophs" not the answer?

Milk does not carry oestrogen that stimulates lactotrophs.

What concept does this question test?

It tests Reproduction: suckling and prolactin in Physiology. As dopamine is the main prolactin-inhibiting factor, lactotrophs are disinhibited and prolactin rises, maintaining milk production.

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 Reproduction: suckling and prolactin?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.