Effect of db-cAMP on total and cell
surface amount of Na,K-ATPase in rat CCDs and in mpkCCDc14
cells. (A and B) Total amount of Na,K-ATPase in control and db-cAMP
treated rat CCDs. Same amounts of microdissected rat CCDs were
incubated in the absence or presence of 10−3 M db-cAMP for
15 min at 37°C. CCDs were then lysed and the Na,K-ATPase α-subunit
was detected by Western blotting using a specific polyclonal antibody.
(A) Representative immunoblot. (B) Bars represent the
densitometric quantification (means ± SE) from four different
experiments. Results are expressed as percentage of the optical density
values from untreated samples (control). (C–F) Cell surface amount of
Na,K-ATPase in control and db-cAMP-treated rat CCDs and
mpkCCDc14 cells. Microdissected rat CCDs or
mpkCCDc14 cells were incubated in the absence or presence
of 10−3 M db-cAMP for 15 min (CCDs) or 30 min
(mpkCCDc14) at 37°C. After biotinyla-tion,
samples were lysed and labeled proteins were precipitated by
streptavidin-agarose beads. The Na,K-ATPase α-subunit was detected by
Western blotting using a specific polyclonal antibody. (C and E)
Representative immunoblots. (D and F) Bars represent the
densitometric quantification (means ± SE) from 12 independent
experiments. Results are expressed as percentage of the optical density
values from untreated samples (control); ∗, p < 0.05 versus
control values.