Figure 7.

Low temperature (20°C) prevented the increased cell surface expression of Na,K-ATPase induced by db-cAMP. Microdissected rat CCDs or mpkCCD_c14 cells were incubated at 20°C in the absence or in the presence of 10⁻³ M db-cAMP for 30 min before biotinylation, lysis, and precipitation by streptavidin agarose-beads. Na,K-ATPase α-subunit was detected by Western blotting as described in Figure 3. (A and C) Representative immunoblots from CCD (A) and mpkCCD_C14 cells (C), respectively. (B and D) Bars represent the densitometric quantification (means ± SE) from 11 and 5 independent experiments for rat CCDs and mpkCCD_c14 cells, respectively. Results are expressed as percentage of the optical density values from untreated samples (control).