Growth Hormone: Gigantism, Acromegaly and Dwarfism
Biology · Chemical Coordination and Integration · NEET
Growth Hormone (GH, or somatotropin) is made by the anterior pituitary. Too much GH in a child causes gigantism (very tall body), too little GH in a child causes pituitary dwarfism (stunted growth), and too much GH in an adult causes acromegaly (thick, disfigured face and hands). Memory hook: "GH is the height hormone in children, but in adults the height door is shut (epiphyseal plates closed), so extra GH only widens bones, not height."
Growth Hormone from the anterior pituitary: excess in a child causes gigantism, excess in an adult causes acromegaly, and deficiency in a child causes pituitary dwarfism. The epiphyseal plate (open in children, closed in adults) decides whether extra GH adds height.
Your doubts, answered
Why does excess growth hormone in adults cause acromegaly and not more height?
Height (linear growth) happens only at the epiphyseal plates (growth plates) of long bones. These plates are open in children but close/fuse after adolescence. So in an adult with extra GH, the bones can no longer grow longer; instead the bones and soft tissue thicken, giving a disfigured face, large jaw, hands and feet. This is acromegaly. GH is still active in adults, so the reason is the closed epiphyseal plates, not inactive GH. This exact idea was asked in NEET 2017.
What is the difference between gigantism and acromegaly?
Both are caused by over-secretion (too much) of Growth Hormone, but the timing decides the result. Gigantism = excess GH in a CHILD (before epiphyseal plates close), so the whole body grows abnormally tall. Acromegaly = excess GH in an ADULT (after plates close), so the person does not get taller but the face, jaw, hands and feet become thick and disfigured. Same hormone, different age = different disease.
What is pituitary dwarfism and how is it different from cretinism?
Pituitary dwarfism is caused by LOW secretion of Growth Hormone in childhood, giving stunted (short) growth but usually normal body proportions and normal mental development. Cretinism is different: it is caused by hypothyroidism (low thyroid hormone) in early life and shows stunted growth WITH mental retardation. NEET often mixes these up, so link GH-deficiency to dwarfism and thyroid-deficiency to cretinism.
Which gland secretes growth hormone and what controls it?
Growth Hormone is secreted by the anterior pituitary (adenohypophysis). It is controlled by the hypothalamus: GHRH (Growth Hormone Releasing Hormone) tells the pituitary to release GH, and somatostatin (GHIH) inhibits its release. So the hypothalamus is the master control above the pituitary for GH.
⚠️ The NEET trap ✗ Excess GH in adults does not raise height because GH becomes inactive in adults. ✓ Excess GH in adults does not raise height because the epiphyseal plates close after adolescence; GH is still active and instead causes acromegaly. 🧠 The reason is a CLOSED growth plate, not a dead hormone. NEET 2017 offered both options to trap you.
Real NEET questions
2017
Hypersecretion of Growth Hormone in adults does not cause further increase in height, because
A · Growth Hormone becomes inactive in adults
B · Epiphyseal plates close after adolescence ✓
C · Bones loose their sensitivity to Growth Hormone in adults
D · Muscle fibres do not grow in size after birth
Solution: Linear (height) growth needs open epiphyseal plates in long bones. After adolescence these plates fuse/close, so even excess GH in adults cannot add height; instead it causes facial and bony disfigurement called acromegaly. GH stays active in adults, so the correct basis is closure of the epiphyseal plates.
2024
Match List I with List II. A. Exophthalmic goiter B. Acromegaly C. Cushing's syndrome D. Cretinism (List II) I. Excess secretion of cortisol, moon face & hyperglycemia II. Hypo-secretion of thyroid hormone and stunted growth III. Hyper secretion of thyroid hormone & protruding eye balls IV. Excessive secretion of growth hormone
A · A-IV, B-II, C-I, D-III
B · A-III, B-IV, C-II, D-I
C · A-III, B-IV, C-I, D-II ✓
D · A-I, B-III, C-II, D-IV
Solution: Acromegaly is caused by excessive secretion of growth hormone, so B-IV. Exophthalmic goitre is hyperthyroidism with protruding eyeballs (A-III), Cushing's syndrome is excess cortisol with moon face (C-I), and cretinism is hypothyroidism with stunted growth (D-II). Correct match: A-III, B-IV, C-I, D-II.
2026
Match List-I with List-II. A. Excess growth hormone B. Luteinizing hormone C. Vasopressin D. Oxytocin (List-II) I. Reabsorption of water and electrolytes in kidney II. Contraction of uterus during child birth III. Acromegaly IV. Ovulation
A · A-III, B-IV, C-II, D-I
B · A-III, B-IV, C-I, D-II ✓
C · A-II, B-IV, C-I, D-III
D · A-IV, B-III, C-I, D-II
Solution: Excess growth hormone in adults leads to acromegaly (A-III). Luteinizing hormone triggers ovulation (B-IV), vasopressin (ADH) causes reabsorption of water and electrolytes in the kidney (C-I), and oxytocin causes contraction of the uterus during childbirth (D-II). Correct match: A-III, B-IV, C-I, D-II.
Solved Chemical Coordination and Integration NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Yes. Somatotropin (STH) and Growth Hormone (GH) are the same hormone, secreted by the anterior pituitary. NEET may use either name.
Does gigantism occur in children or adults?
Gigantism occurs in children, when excess GH acts while the epiphyseal plates are still open, so the whole body grows very tall. In adults the same excess causes acromegaly instead.
Is dwarfism due to excess or deficiency of GH?
Pituitary dwarfism is due to deficiency (low secretion) of Growth Hormone in childhood, giving stunted growth with normal body proportions.
Which hormone from the hypothalamus stops GH release?
Somatostatin (also called GHIH, Growth Hormone Inhibiting Hormone) from the hypothalamus inhibits the release of GH from the anterior pituitary.
Why is acromegaly hard to diagnose early?
Per NCERT, acromegaly develops slowly and the disfigurement of the face, hands and feet appears gradually, so it often goes undetected for years until the external changes become obvious.
