CHLORIDE COMPARTMENTS OF FROG LENS AND CHLORIDE PERMEABILITIES OF ITS ISOLATED SURFACES

Abstract

Total Cl- content and exchangeable Cl- pools of isolated bullfrog [Rana catesbeiana] lens and Cl- permeabilities of its isolated anterior and posterior surfaces were determined. Cl- content was 2.81 .mu.eq, corresponding to a cellular concentration of 13.3 mM. After 18 h incubation, Cl- content increased to 3.84 .mu.eq. Three Cl- compartments were found: a fast compartment (t1/2 = 13 min), probably extracellular; a slow compartment (t1/2 = 160 min), probably intracellular; and a bound fraction (24% of the total Cl-). 36Cl- efflux across anterior and posterior lens surfaces was similar. When a correction for the asymmetrical electrical potential difference was made, the permeability of the posterior side, 46.9 .times. 10-7 cm/s, was nearly twice the permeability of the anterior side, 27.6 .times. 10-7 cm/s. The Cl- movement and distribution seemed to obey passive forces. Iodoacetate increased both total Cl- and exchangeable Cl- but had little effect on the rate of Cl- exchange. Total Cl- gain by lenses incubated at 2.degree. C was similar to the control. The exchangeable Cl- pools and the rate of exchange were significantly diminished.