GnRH is released in a pulsatile fashion. What is the physiological consequence of continuous (non-pulsatile) GnRH administration as used in the treatment of precocious puberty?

• A Upregulation of pituitary GnRH receptors increasing LH and FSH
• B Downregulation of pituitary GnRH receptors reducing LH and FSH ✓
• C Stimulation of hypothalamic kisspeptin pathways amplifying GnRH
• D Direct inhibition of gonadal steroidogenesis independent of gonadotropins

Explanation

Pulsatile GnRH is required for normal pituitary responsiveness because it allows receptor recycling and resensitization between pulses. Continuous GnRH exposure causes receptor downregulation and desensitization of gonadotrophs, paradoxically suppressing LH and FSH secretion. This principle is exploited therapeutically: GnRH agonist analogues given continuously (leuprolide, goserelin) initially cause a 'flare' then produce a state of medical gonadectomy, used in precocious puberty, prostate cancer, and endometriosis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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