FIG. 7.

The exocytotic defect in ABCA1^−P/−P β-cells is rescued by acute intracellular cholesterol depletion. A: Whole-cell membrane capacitance from β-cells after intracellular dialysis with a low (10 μmol/L) concentration of MβCD to deplete cholesterol via the cell interior. B: Membrane capacitance during co-infusion of 200 nmol/L free–Ca²⁺ together with 10 μmol/L MβCD or an equal concentration of DMSO. C: The total capacitance increase, normalized to initial cell size, at 200 s after Ca²⁺ infusion (n = 13–16). D: The exocytotic response to a series of ten 500-ms depolarizations rescued in ABCA1^−P/−P β-cells by intracellular cholesterol depletion. E: The cumulative capacitance response of ABCA1^+/+ (n = 21, ○) and ABCA1^−P/−P β-cells dialyzed with DMSO (n = 23, □) or 10 μmol/L MβCD (n = 20, ■). For clarity, the ABCA1^+/+ + MβCD group is not shown, although this was not different from controls. *P < 0.05 and **P < 0.01 compared with controls.