Given below are statements about ion transport proteins in pancreatic duct cells which influence the composition of pancreatic juice:
A. Primary Cl⁻/HCO₃⁻ exchanger is located on the luminal side.
B. CFTR is located primarily on the basolateral side.
C. Na⁺–bicarbonate cotransporter is located on the basolateral side.
D. Na⁺/hydrogen exchanger-1 is located on the luminal side.
Which one of the following options has a combination of all correct statements?

Correct option is C

Correct Answer:
(c) A and C
Explanation:
Pancreatic duct cells secrete bicarbonate-rich fluid. The Cl⁻/HCO₃⁻ exchanger responsible for bicarbonate secretion functions at the luminal (apical) membrane, making statement A correct.
The Na⁺–HCO₃⁻ cotransporter brings bicarbonate into the cell from blood across the basolateral membrane, supporting bicarbonate secretion and making statement C correct.
Information Booster :
· Pancreatic juice is highly alkaline due to active HCO₃⁻ secretion.
· CFTR provides luminal Cl⁻ to drive Cl⁻/HCO₃⁻ exchange.
· Coordinated apical–basolateral transport maintains ionic balance.
· Defects in CFTR impair bicarbonate secretion (e.g., cystic fibrosis).
Additional Information (Incorrect Options):
Statement B: Incorrect — CFTR is located on the luminal (apical) membrane, not basolateral.
Statement D: Incorrect — Na⁺/H⁺ exchanger-1 (NHE1) is primarily basolateral, involved in intracellular pH regulation.
Hence, options including B or D are incorrect.