Table 1.

Proton conductance and acid secretion of lung epithelial cells

Lung Cell Type	Species	Characteristics	Whole cell conductance, (pS/pF)	Epithelial acid Secretion nmole·h-1·cm-2	reference
Ciliated	Human	Primary tracheal	20	410	(17, 18)
				460
Mixed	Human	Primary sinonasal	--	1070 2)	(20)
Calu-3	Human	Serous-like gland cell line	12	22	(18)
JME	Human	Nasal epithelial cell line, CF genotype	9	125	(17, 19)
Type II	Human	Primary fetal alveolar	10 3)	80	(14)
Type II	Rat	Primary alveolar	150 1)	--	(2)
A549	Human	Type II-like cell line	11 1)	--	(76)

Whole cell conductance is given at 0 mV for recordings at room temperature; epithelial acid secretion is the Zn²⁺-sensitive fraction of total at a mucosal pH of 7.3.

¹⁾original value adjusted to one pH unit gradient;

²⁾Original value adjusted to mucosal pH of 7.3 using the pH-dependence in (19);

³⁾H. Fischer, unpublished;

^--, not determined.