Anterior pituitary: growth hormone axis: 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 · Anterior pituitary: growth hormone axis

Sample item

A 6-year-old boy has severe short stature, with a raised growth hormone and a low IGF-1 level. He does not respond to growth hormone therapy. What is the most likely defect?

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

The answer and the reasoning

C. Growth hormone receptor defect

In Laron syndrome the growth hormone receptor is defective, so the liver cannot generate IGF-1 in response to growth hormone. The loss of IGF-1 negative feedback causes high growth hormone levels. Treatment is with recombinant IGF-1, not growth hormone.

Option by option

  • A. Hypothyroidism with low TSH

    Hypothyroidism would not raise growth hormone with unresponsiveness to therapy.

  • B. Hypothalamic GHRH deficiency

    GHRH deficiency would also give low growth hormone and a response to GH.

  • C. Growth hormone receptor defect (correct)

    Correct. Receptor failure gives high GH, low IGF-1 and no response to GH.

  • D. Growth hormone deficiency from pituitary hypoplasia

    GH deficiency would give low growth hormone, and the child would respond to treatment.

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, Growth hormone receptor defect. In Laron syndrome the growth hormone receptor is defective, so the liver cannot generate IGF-1 in response to growth hormone.

Why is "Hypothyroidism with low TSH" not the answer?

Hypothyroidism would not raise growth hormone with unresponsiveness to therapy.

Why is "Hypothalamic GHRH deficiency" not the answer?

GHRH deficiency would also give low growth hormone and a response to GH.

Why is "Growth hormone deficiency from pituitary hypoplasia" not the answer?

GH deficiency would give low growth hormone, and the child would respond to treatment.

What concept does this question test?

It tests Anterior pituitary: growth hormone axis in Physiology. The loss of IGF-1 negative feedback causes high growth hormone levels. Treatment is with recombinant IGF-1, not growth hormone.

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 Anterior pituitary: growth hormone axis?

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.