## Info

Equations

Basis of the equations

(1)

tp = af

Na+ pump (af known)

(2)

tn2b = bf

Na+-2HCO3- cotransporter (bf known)

(3)

tc = cf

Cl- channel (cf known)

(4)

tn = df

epithelial Na+ channel (df known)

(5)

tkb + tp + tn2b = Foc

basolateral K+ channel/s (Foc known)

(6)

tn2b + tp + tkb = tn + 2"tn3b + tc - tka

Cellular electroneutrality

(7)

tnk2c + 2"tp = tka + tkb

K+ conservation

(8)

tn + tnh + tn2b + tnk2c = 3*tp + tn3b

Na+ conservation

(9)

2'tn2b = 3'tn3b + tcb

HCO3- conservation

(10)

2'tnk2c + tcb = tc

Cl- conservation

(11)

th = tnh + thA

H+ conservation

The five symbols in Eqs. 1-5, af, bf, cf, df, and Foc, represent flux values obtained from experiments. The 11 parameters used in the model begin with a 't because they represent rates of turnover (or element fluxes) for the given transporters and ion channels (or elements).

The five symbols in Eqs. 1-5, af, bf, cf, df, and Foc, represent flux values obtained from experiments. The 11 parameters used in the model begin with a 't because they represent rates of turnover (or element fluxes) for the given transporters and ion channels (or elements).

(1) tn (sodium channel); (2) tn3b (sodium, three-bicarbonate cotransporter); (3) tka (apical potassium channels); (4) tc (chloride channels); (5) thA (hydrogen-ATPase); (6) tp (sodium pump); (7) tn2b (sodium, two-bicarbonate cotransporter); (8) tnk2c (sodium, potassium, two-chloride cotransporter); (9) tcb (chloride/bicarbonate exchanger); (10) tkb (basolateral potassium channels); (11) tnh (sodium/hydrogen exchanger).

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