AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 3 284-G289, Copyright © 1984 by American Physiological Society
Alpha 1-adrenergic inhibition of protein synthesis in rat submandibular cells
T. Takuma, B. L. Kuyatt and B. J. Baum
The incorporation of [14C]leucine into protein in dispersed cells from rat
submandibular gland was inhibited by epinephrine. The dose required for a
half-maximal effect was approximately 10(-6) M. This sensitivity is similar
to that of mucin and potassium secretion induced by epinephrine from these
cells. The inhibitory effect of epinephrine was mediated by the activation
of alpha 1-adrenergic receptors and was partially independent of
extracellular calcium. The calcium ionophore A23187 also decreased protein
synthesis in the presence and absence of extracellular calcium. Epinephrine
diminished alpha-[14C]aminoisobutyric acid (AIB) influx, but the extent of
altered AIB uptake was much less than the extent of decrease in protein
synthesis. Analysis of newly synthesized protein by gel electrophoresis and
autofluorography showed that epinephrine selectively inhibited the
synthesis of specific submandibular proteins. In aggregate these results
suggest that activation of alpha 1-adrenergic receptors in rat
submandibular cells influences the regulation of protein synthesis by a
mechanism that uses intracellular calcium.
