Chronic Kidney Disease USMLE Step 1 Practice Question
A 35-year-old male presents with severe dehydration following prolonged exercise without fluid intake. Vital signs show BP 95/60, HR 118, RR 20, and serum osmolality 310 mOsm/kg. Urine specific gravity is 1.035 with minimal urine output. He denies diuretic use. His kidneys respond by increasing aquaporin-2 channel insertion into collecting duct principal cell apical membranes, enhancing water reabsorption. Which hormone mediates this adaptive response?
Answer choices
- AParathyroid hormone
- BAntidiuretic hormoneCorrect answer
- CRenin
- DAldosterone
- EAtrial natriuretic peptide
- FVasopressin-releasing peptide
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