Characterization of the concanavalin A-induced increase in lymphocyte cell membrane permeability by furosemide

The effect of ConA on passive 42K+ fluxes in human lymphocytes was analysed by treatment with furosemide and ouabain. Furosemide has no effect on net K+ transport and pump flux. The component of passive efflux of 42K+ which depends on K+-K+ exchange is inhibited by furosemide; its mechanism is discussed in detail. The 42K+ uptake in lymphocytes consists of 1. an ouabain-sensitive pump influx, 2. an ouabain-insensitive leak influx and 3. a furosemide-sensitive K+-K+-exchange. Only the first two components of 42K+ uptake are stimulated by ConA.