Decrease of plasma membrane area during differentiation. Resting plasma membrane area (left scale) was determined from initial capacitance (right scale) in 81 cells from three different cultures after different times in culture. Data points are mean ± SD. The continuous line is a third order polynomial fit. The mean value of mature cells is indicated by the dashed line (2.9 ± 0.3 pF, SD, n = 30).