A 34-year-old woman with a history of severe postpartum hemorrhage 2 years ago now presents with fatigue, cold intolerance, and failure of lactation. Laboratory evaluation reveals low free T4 with inappropriately low TSH, and low cortisol with inappropriately low ACTH. MRI shows an empty sella. The hypothalamic nuclei responsible for synthesizing the hypophysiotropic hormones that drive the thyrotrophs and corticotrophs are located in which structure?
- A Supraoptic nucleus
- B Paraventricular nucleus ✓
- C Arcuate nucleus
- D Ventromedial nucleus
Correct answer: B. Paraventricular nucleus
Explanation
The paraventricular nucleus (PVN) contains parvocellular neurons that synthesize TRH and CRH, which are released into the hypophyseal portal system to drive thyrotrophs and corticotrophs. The patient has Sheehan syndrome causing panhypopituitarism. The supraoptic nucleus synthesizes ADH, arcuate nucleus contains GHRH/NPY neurons, and VMH is the satiety center.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.