Fig. 5. Effects of chlorate and BzlGalNAc on basal and stimulated secretion of
newly made proteins. (A) Phosphorimage of secreted
[35S]met/cys-labeled proteins. Pulse-labeled acini were washed and
chased at 1 mg cell protein per ml in the indicated buffers. During the final
30 minutes of chase, 1 µM carbachol and 1 mM 8-Br-cAMP were added to
stimulate regulated secretion (S). The lane marked `0' is 10% of a time zero
pellet (0 hour chase) used to quantify the percentage release values. (B) The
effect of 30 mM chlorate on basal and stimulated secretion (arrow indicates
addition of stimulus for final 30 minutes of chase) of
[35S]met/cys-labeled proteins. Amylase release was quantified
relative to cell content just after the pulse labeling. Data are
means±s.e., n=4 independent experiments. (C) The effect of 32
mM BzlGalNAc on basal and stimulated secretion (arrow indicates addition of
stimulus for final 30 minutes of chase) of [35S]met/cys-labeled
proteins. For comparison, the control data from panel B are reproduced here.
Data are means±s.e.m., n=4 independent experiments.
*P=0.005 compared with the DMSO control after stimulation.
(D) Quantification of basal and stimulated secretion (arrow indicates addition
of stimulus for final 30 minutes of incubation) of prestored protein by
Coomassie blue staining of secreted media from a representative independent
experiment. (E) Quantitation of [35S]labeled amylase 6 hours after
chase under the different conditions. Data are expressed as a percentage of
initial level of labeled amylase; means±range of values from two
independent experiments.