THE EFFECT OF THYROID HORMONES ON WATER PERMEABILITY OF THE ISOLATED BLADDER OF THE TOAD BUFO BUFO

SUMMARY Thyroxine at 10−6m concentration enhances water movement from the mucosal to the serosal surface of the isolated toad bladder in the absence of an osmotic gradient. It is suggested that this is caused by the effect of thyroxine on sodium transport which creates a driving force for the increased water movement. Thyroxine caused this effect when applied on either side of the membrane, but was more effective when applied to the serosal surface. Incubation of different bladders successively in the same triiodothyronine solution indicated that triiodothyronine may be rapidly utilized. A mixture of thyroxine and triiodothyronine caused a diphasic effect on water loss down an osmotic gradient. The analogues tetraiodothyroproprionic acid and tetraiodothyroformic acid had no effect on water movement down an osmotic gradient across the isolated toad bladder nor did they affect oxygen uptake or sodium transport. The results support the concept that thyroxine and triiodothyronine act on permeability processes in and across cell membranes.

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PERMEABILITY AND RESPIRATION EFFECTS OF THYROIDAL HORMONES ON THE ISOLATED BLADDER OF THE TOAD BUFO BUFO

Journal of Endocrinology ◽

10.1677/joe.0.0250411 ◽

1963 ◽

Vol 25 (4) ◽

pp. 411-425 ◽

Cited By ~ 20

Author(s):

A. J. MATTY ◽

K. GREEN

Keyword(s):

Oxygen Uptake ◽

Water Loss ◽

Enzyme Inhibitors ◽

Water Movement ◽

Bufo Bufo ◽

Metabolic Energy ◽

Toad Bladder ◽

Osmotic Gradient ◽

Close Relationship ◽

Toad Bufo

SUMMARY l-Thyroxine and 3,5,3′-triiodo-l-thyronine in concentrations of 10−8 m to 10−5 m were shown to increase the oxygen uptake and water transfer down an osmotic gradient in the isolated urinary bladder of Bufo bufo. The increase in water transport after treatment with thyroxine and triiodothyronine was related linearly to the log dose. The increase in O2 uptake and water movement in equimolar concentrations of thyroxine and triiodothyronine were similar but the responses to the latter were more rapid. Substitution of sodium ions by choline in the incubation medium resulted in a fall of oxygen uptake by the bladder, and a slight lowering of water loss. When thyroxine was added, oxygen uptake increased to the same extent in both media but only in sodium saline did water loss increase greatly. Specific enzyme inhibitors prevented the thyroxine-induced increase in water loss across the isolated toad bladder, indicating that metabolic energy is necessary for this alteration in permeability. Triiodothyronine and thyroxine caused an increased water loss across the isolated toad bladder when placed on either the mucosal or serosal surface. Two analogues of the thyroid hormones, 3,5,3′-triiodothyroacetic acid and 3,5,3′,5-tetraiodothyroacetic acid, caused an extremely rapid, but transient, movement of water across the bladder; their action and that of triiodothyronine and thyroxine is compared. An hypothesis is proposed tentatively to account for the mode of action of thyroxine on the permeability of the isolated toad bladder, taking into account the close relationship between increases in water permeability and metabolism, particularly that involving sodium transport.

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Water Transfer by The Toad Bladder

Jurnal Agripet ◽

10.17969/agripet.v1i1.3109 ◽

2000 ◽

Vol 1 (1) ◽

pp. 10-14

Author(s):

Sulaiman Ibrahim

Keyword(s):

Water Movement ◽

Water Transfer ◽

Toad Bladder ◽

Bathing Solution ◽

Osmotic Gradient ◽

Serosal Surface ◽

Time Period ◽

Initial Control ◽

Solution Bathing ◽

Toad Bufo

ABSTRACT. Studies have been made on the isolated urinary bladder of the toad, Bufo marinus, in an attempt to investigate the effect of vasopressin on the permeability of water from mucosal surface to serosal surface of the toad bladder. The method adapted was that described by Bentley ( 1 ). The bilobed bladder of the toad is devided into two separate sacs. Each of the sacs is filled with a dilute Ringers solution and then immersed in aerated isotonic Ringers solution. The rate of water loss along the imposed osmotic gradient is estimated by weighing the sacs in air at 30 minute intervals and nothing the weight loss in that time period. In most studies one bladder sac serves as a control for the contra lateral experimental obtained from the same animal. Osmotic flow of water is negligible in both sacs during the initial control periods. However, the addition of vasopressin to the solution bathing the serosal surface of the membrane result in a market increase in net water movement. The effect is readily reversed by rinsing the bladder and adding hormone free Ringgers solution to the serosal surface. Characteristically no response is elicited by addition of hormone to the mucosal bathing solution.

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OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN

Journal of Endocrinology ◽

10.1677/joe.0.0670119 ◽

1975 ◽

Vol 67 (1) ◽

pp. 119-125

Author(s):

P. J. BENTLEY

Keyword(s):

Urinary Bladder ◽

Water Movement ◽

Short Circuit ◽

Electrical Potential ◽

Short Circuit Current ◽

Toad Bladder ◽

Toad Urinary Bladder ◽

Electrical Potential Difference ◽

Osmotic Gradient

SUMMARY The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small. Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased. This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced. The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present. The physiological implications of these observations and the possible mechanisms involved are discussed.

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