Endocrinology: growth hormone: 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.

Try it

Physiology · Endocrinology: growth hormone

Sample item

A 9-year-old boy with short stature has an undetectable random serum growth hormone. Why is serum IGF-1 preferred as the first screening test for deficiency?

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

The answer and the reasoning

A. Growth hormone is secreted in pulses and is low between them, while IGF-1 has a long half-life and reflects integrated secretion

Growth hormone is released in bursts, mostly during deep sleep, so a single random level is often undetectable even in healthy children. Its effects on growth are largely mediated by hepatic IGF-1, which is bound to binding proteins and varies little during the day, so it is a stable indicator of overall GH secretion.

Option by option

  • A. Growth hormone is secreted in pulses and is low between them, while IGF-1 has a long half-life and reflects integrated secretion (correct)

    Correct. Pulsatile secretion makes random GH unreliable, and IGF-1 is stable.

  • B. IGF-1 is made in the pituitary together with growth hormone

    IGF-1 is produced mainly by the liver, not the pituitary.

  • C. Growth hormone is stable in plasma and IGF-1 rises sharply only after meals

    GH has a short half-life and IGF-1 does not vary acutely with meals.

  • D. IGF-1 is secreted only during hypoglycaemia

    IGF-1 is not restricted to hypoglycaemia; GH is the hormone stimulated by it.

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.

More Physiology questions

Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is A, Growth hormone is secreted in pulses and is low between them, while IGF-1 has a long half-life and reflects integrated secretion. Growth hormone is released in bursts, mostly during deep sleep, so a single random level is often undetectable even in healthy children.

Why is "IGF-1 is made in the pituitary together with growth hormone" not the answer?

IGF-1 is produced mainly by the liver, not the pituitary.

Why is "Growth hormone is stable in plasma and IGF-1 rises sharply only after…" not the answer?

GH has a short half-life and IGF-1 does not vary acutely with meals.

Why is "IGF-1 is secreted only during hypoglycaemia" not the answer?

IGF-1 is not restricted to hypoglycaemia; GH is the hormone stimulated by it.

What concept does this question test?

It tests Endocrinology: growth hormone in Physiology. Its effects on growth are largely mediated by hepatic IGF-1, which is bound to binding proteins and varies little during the day, so it is a stable indicator of overall GH secretion.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Endocrinology: growth hormone?

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.