title: Stimulation of urinary acidification by aldosterone and inhibitors of RNA and protein synthesis.
abstract: Urinary acidification by the urinary bladder of the toad (Bufo marinus) was stimulated, relative to control, by the in vitro addition of aldosterone (10(-7) M), actinomycin D (20 microgram/ml), puromycin (80 microgram/ml) or cycloheximide (5 microgram/ml). The action of the inhibitors of RNA or protein synthesis was not additive with that of aldosterone. This is opposite to the situation with Na+ transport, where the stimulation by aldosterone is abolished by the same concentrations of these inhibitors. That all agents enhanced urinary acidification was verified by: (i) measurement of RSCC (reverse short-circuit current) in the absence of Na+ transport, (ii) inhibition of RSCC by acetazolamide, an inhibitor of carbonic anhydrase, and (iii) direct measurement of the pH change of the mucosal (urinary) fluid. As in the case of Na+ transport, spirolactone inhibited the action of aldosterone. Although not a unique model, the apparent paradoxical mimicry of aldosterone's stimulation of urinary acidification may be explained by a model which includes action of aldosterone and the inhibitors via their known effects on RNA and protein synthesis.
mesh_terms: D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects*; D002024:Bufo marinus; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D011691:Puromycin / Q000494:pharmacology; D014556:Urine / Q000378:metabolism
chemical_list: D000963:Antimetabolites; D003609:Dactinomycin; D000450:Aldosterone; D011691:Puromycin; D006859:Hydrogen; D003513:Cycloheximide