Glycerol permeation of the human granulocyte

This communication presents a study of the glycerol permeability of the human granulocyte. The study was undertaken to facilitate the use of glycerol as a cryoprotective agent. Granulocytes were purified by centrifugation-elutriation and permeability measured both in monolayer and suspension. Cell permeability was determined by following the passage of 3H-glycerol across the cell membrane. Glycerol efflux was measured at concentrations ranging from 1 microM to 1750 mM (2100 mOsm) under isosmotic and hypotonic conditions. Influx was determined at concentrations between 1 and 100 mM. The monolayer and suspension assays yielded similar kinetics for efflux. Both influx and efflux kinetics were biphasic. The permeability coefficient for efflux was independent of concentration. Since the kinetics were curvilinear, they could not be completely described by a single permeability coefficient. However, "average" values were computed and found to be 1.7 x 10(-5) cm/min for efflux, and 2.8 x 10(-5) cm/min for influx.