title: Evidence for more than one mechanism of action of the glucocorticoid hormones.
abstract: The data presented here provide evidence for at least two major cellular responses to the glucocorticoid hormones that do not seem to involve an interaction between the activated hormone-receptor complex and chromatin. We observed that 5mM pyridoxine in L-cell culture medium both increases the intracellular content of free pyridoxal phosphate by about 30% and decreases the glucocorticoid induction of glutamine synthetase to less than 30% of that at the normal (5 microM) concentration of the vitamin. Two other responses to the hormone-a major decrease in the polysome content of the cells and a decrease in the state of phosphorylation of ribosomal protein S6-are unaffected by the 5mM dose of the vitamin. In light of the findings of DiSorbo and Litwack ((1981) Biochem. Biophys. Res. Commun. 99, 1203-1208), pyridoxal phosphate appears to modulate the enzyme-inducing activity of dexamethasone in L-cells but not the polysome and ribosome related changes. These results are consistent with the hypothesis that certain important glucocorticoid induced responses are independent of nuclear function.
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D007700:Kinetics; D007739:L Cells / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000378:metabolism; D011736:Pyridoxine / Q000494:pharmacology; D012269:Ribosomal Proteins / Q000378:metabolism
chemical_list: D012269:Ribosomal Proteins; D011732:Pyridoxal Phosphate; D003907:Dexamethasone; D005974:Glutamate-Ammonia Ligase; D011736:Pyridoxine