Calcium release in relation to permeability changes in toad bladder epithelium following antidiuretic hormone

摘要: 1. Methods for measuring the release of 45Ca from isolated urinary bladders toads (Bufo marinus) pre-loaded with this isotope have been devised. One method allowed separate collection mucosal and serosal surfaces bladders. 2. Reducing ambient calcium concentration reduced rate efflux suggesting that radiolabel represents exchange. 3. Antidiuretic hormone, theophylline prostaglandin E1 all increased efflux, while lanthanum amphotericin were without effect. Cyclic AMP caused only an inhibition release. 4. The increase in due to antidiuretic hormone came exclusively side. Experiments EGTA suggest entering solution arises mainly superficial sites membrane. 5. by was not influenced removal sodium bathing solution. Low pH amiloride or abolished hormone. 6. time course surface rapid (commencing between 0·5 1·5 min after application). Thus precedes transport hydro-osmotic flow following appears be at least as cyclic generation tissue. 7. relationship exchange permeability changes bladder water sodium, are discussed.