Growth hormone secretion is regulated by two opposing hypothalamic hormones. A 14-year-old boy with short stature is found to have a deficiency of the stimulatory hormone. Which hypothalamic hormone is deficient?

• A Somatostatin (SST)
• B Thyrotropin-releasing hormone (TRH)
• C Growth hormone-releasing hormone (GHRH) ✓
• D Gonadotropin-releasing hormone (GnRH)

Explanation

Growth hormone secretion is stimulated by GHRH and inhibited by somatostatin (SST), both secreted by the hypothalamus. GHRH binds Gs-coupled receptors on somatotrophs, increasing cAMP and GH release. Deficiency of GHRH leads to GH deficiency and consequent short stature due to reduced IGF-1 production in the liver. Somatostatin deficiency would paradoxically increase GH, not decrease it.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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