GI System MCAT Practice Question
A clinical study examines patients with loss-of-function mutations in the SGLT1 transporter, which normally co-transports sodium and glucose in small intestinal enterocytes. Affected patients develop osmotic diarrhea when consuming glucose-rich meals, despite normal glucose oxidation rates in hepatocytes. The primary mechanism underlying their diarrhea involves which consequence of defective SGLT1 function?
Answer choices
- ADecreased hepatic glycolysis preventing glucose utilization
- BIncreased luminal glucose concentration creating osmotic gradient favoring water secretionCorrect answer
- CEnhanced fructose absorption competing for GLUT5 transporters
- DReduced sodium reabsorption decreasing basolateral Na+/K+ ATPase activity
- EImpaired tight junction claudins from genetic linkage to SGLT1 mutations
- FDecreased intestinal ATP production reducing active transport of all nutrients
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