A 44-year-old man presents to the physician for a routine health maintenance examination. Serum studies show a decreased vitamin D level. He works in an office and says he infrequently gets outside. He eats plenty of fish and dairy. Direct production of which molecule in this patient is decreased as a result of not getting adequate sunlight?
1,25-(OH)2-D3 (calcitriol)
24,25-(OH)2-D3
25-OH-D3 (calcidiol)
7-dehydrocholesterol
Cholecalciferol
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Cut-to-the-chase Answer (1:17):
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HY USMLE Answer (4:19):
