The Effects of Neurohypophysial Extracts on Water Transfer Across the Wall of the Isolated Urinary Bladder of the Toad Bufo Marinus

Abstract

1. An in vitro preparation of the urinary bladder of Bufo marinus is described. 2. Small doses of 'Pituitrin' markedly increase the rate of water transfer across the bladder wall when the solutions inside the bladder are hypotonic.3. Passive movement is small and increases slightly with increases in the osmotic gradient across the bladder wall. It is unaffected by changes in substrate levels or any of the metabolic inhibitors tested except for cyanide which increases it in some cases.4. The vasopressor neurohypophysial fraction is more active than the oxytocic one in increasing water transfer across the bladder wall.5. The increase in water transfer depends on an intact oxygen supply and sufficient glucose or pyruvate.6. Iodoacetate, malonate, cyanide, 2-4-dinitrophenol, and bubbling 5% CO2+95% O2 through Ringer's solution inhibit the water transfer in response to neurohypophysial extract. 7. Diamox is only an effective inhibitor at very high concentrations. 8. The possible mechanism of the water transfer is discussed.The reabsorption of water stored in the urinary bladder of Bufo regularis when injected with neurohypophysial extract has been shown by Ewer [1952]. The possi¬ bility that the water may have been absorbed after régurgitation into the cloaca was eliminated by Sawyer & Schisgall [1956], who concluded that the water was in fact transferred across the bladder wall.Preparations of frog and toad skin in vitro have been used for the study of the movements of water and salt across biological membranes [see Sawyer, 1956]. From Ewer's observations it seemed likely that the isolated urinary bladder of the toad could be used for similar studies. Moreover, the simpler histological structure, in particular the absence of the numerous secretory glands present in the frog and toad skin, might clarify interpretation of results. The experiments reported in this paper demonstrate that the isolated bladder of the toad is a very suitable preparation for the study of neurohypophysial effects on water transport in vitro. Results are also presented from a continuing investigation of factors which influence the effect of neurohypophysial extracts. 13Endoc. 17, 3

Action of amphotericin B on the toad bladder: evidence for sodium transport along two pathways

“…The bladders were set up to measure water transfer and sodium transport as described previously (Bentley, 1958(Bentley, , 1960. Each lobe of the bladder was dissected from pithed toads and placed in Ringer solution of the following composition (mM): NaCl, 111; KCI, 3'35; CaCl2, 2-7; NaHCO3, 4-0 and glucose, 5.5.…”

Inhibition by diuretics of cyclic 3′,5′‐AMP‐dependent protein kinase from toad bladder epithelium

“…Neurohypophysial hormones increase the transport of sodium from the mucosal to the serosal surface (Leaf, Anderson & Page, 1958) and also the osmotic flow of water in the same direction (Bentley, 1958). These actions of neurohypophysial hormones are thought to be mediated by cyclic 3', 5'-adenosine monophosphate (cAMP) as an intracellular second messenger (Orloff & Handler, 1962;Bar, Hechter, Schwartz & Walter, 1970).…”

Some aspects of the inhibition of the action of antidiuretic hormone by lithium ions in the rat kidney and bladder of the toad Bufo marinus

“…Toads Toads (Bufo marinus) were double pithed. Each lobe of the bladder was removed and quickly placed in Bentley Ringer (Bentley (1958): NaCl, 111 mmol/l. ; Ca C12, 3 35 mmol/l.…”

“…The Bentley Ringer was constantly aerated by water vapour, saturated air being pumped through the solution. The procedure followed, including washing and emptying between assays, was as recommended by Bentley (1958) and included a test period of 40 min to demonstrate the absence of leaks. The preparation was accepted as satisfactory if the weight change was less than 50 mg. Further periods were used to study the effects of alterations of the fluid on the mucosal or serosal surface on the passage of water facilitated by (a) antidiuretic hormone and (b) adenosine 3',5'-monophosphate (cyclic AMP) in the serosal fluid.…”