Aquaporin-10 Represents an Alternative Pathway for Glycerol Efflux from Human Adipocytes
Figure 5
Water and glycerol permeability of human adipocyte plasma membrane vesicles.
(A) Representative light scattering curves were obtained by exposing the isolated adipocytes to a 150 mOsm osmotic gradient in two different conditions: normal untreated cells (Control) and cells treated for 15 min with 0.5 M DMSO (DMSO). (B) Bars represent water permeability of isolated adipocytes, expressed as relative k. Values are means ± SEM of at least 15 single shots for each of five different adipocyte preparations. *, P<0.05 vs Control (Student t test for pair data). (C) Representative light scattering curves were obtained by exposing the adipocytes plasma membrane vesicles to a 150 mOsm osmotic gradient in three different conditions: normal untreated vesicles (Control), vesicles treated for 10 min with 1 mM HgCl2, vesicles treated with 1 mM HgCl2 followed by 15 min treatment with 15 mM β-mercaptoethanol (β-ME). (D) Bars represent water permeability of adipocyte plasma membrane vesicles, expressed as relative k. Values are means ± SEM of at least 8 single shots for each of five different preparations. *, P<0.05 vs Control and β-ME (repeated measure ANOVA, followed by Newman-Keuls’s Q test). (E) Representative light scattering curves were obtained by exposing the adipocytes plasma membrane vesicles to a 150 mM inwardly directed gradient of glycerol. The initial increase in light scattering results from osmotic water efflux caused by vesicle shrinkage (before the dashed line), while the subsequent slower decrease is caused by glycerol entry (after the dashed line). (F) Water (Pf) and glycerol (Pgly) permeability coefficients were calculated as described in Materials and Methods.