. Author manuscript; available in PMC: 2013 May 30.

Published in final edited form as: Physiol Rev. 2012 Jan;92(1):39–74. doi: 10.1152/physrev.00011.2011

Table 1.

Transporters in the luminal (apical) membrane of exocrine gland ducts

Transporter	Protein	Role	References
cAMP-activated Cl⁻ channel	CFTR (ABCC7)	Fluid and HCO₃⁻ secretion	^{(126), (127), (125), (128), (4), (312), (296), (26), (261), (68), (466), (183), (103), (175), (174), (245), (340), (353), (387), (182), (84), (324), (402), (61)}
Ca²⁺-activated Cl⁻ channel	TMEM16/Anotcamin family (?)	(?)	^{(128), (444), (108), (443), (105), (296), (4), (158), (21), (176), (39), (452), (51), (52), (55), (345), (476), (459), (43), (383)}
Anion exchangers		HCO₃⁻ secretion	^{(47), (220), (19), (407), (306), (471), (235), (153), (20), (97), (291), (238), (213), (386), (401), (183), (179), (178)}
	SLC26A3 (DRA/CLD)	HCO₃⁻ secretion, electrogenic 2Cl⁻/1HCO₃⁻ exchanger	^{(96), (273), (129)}
	SLC26A6 (PAT1)	Fluid and HCO₃⁻ secretion, electrogenic 1Cl⁻/2HCO₃⁻ exchanger	^{(96, 247), (429), (209), (190), (434), (449), (213), (235), (215), (122)}
Na⁺/H⁺ exchangers	NHE3 (SLC9A3)	HCO₃⁻ reabsorption (HCO₃⁻ salvage)	^{(118), (263), (471), (264), (234)}
Na⁺/H⁺ exchangers	NHE2 (SLC9A2)	(?)	^{(118), (263), (471), (264), (234)}
Na⁺-HCO₃⁻ cotransporter	NBCn1-A (NBC3, SLC4A7)	HCO₃⁻ reabsorption (HCO₃⁻ salvage) ?	^{(327), (59), (250)}
K⁺ channels	Maxi- K⁺ channels (KCNMA1?)	Maintain membrane potential during stimulated secretion	⁽⁴²³⁾
Water channel	Aquaporin 5 (AQP5)	Fluid secretion	⁽⁴²⁾
Epithelial Na⁺ channel (ENaC)	SCNN1A (α), SCNN1B (β), SCNN1G (γ), SCNN1D (δ)	Na⁺ absorption (Functional ENaC channel with αβγ subunits is expressed in salivary, but not in pancreatic duct. ENaCδ is expressed in pancreas; however its role is uncertain.)	^{(49, 65, 454)}