Effect of neurohypophysial hormones on fluid movement across isolated bladder of Rana cancrivora, Rana temporaria and Bufo melanostictus

Dicker, S. E.; Elliott, Annie B.

doi:10.1113/jphysiol.1970.sp009200

Cited by 21 publications

(14 citation statements)

References 19 publications

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“…Dicker & Elliott (1970 a, 6) examined the sensitivity of the skin and bladder of R. can¬ crivora, and found that in respect to water permeability the skin was not appreciably affected by neurohypophysial peptides, and that the urinary bladder was less responsive to these hormones than were bladders of freshwater amphibians. They also reported (Dicker & Elliott, 19706) that the neurohypophysis of R. cancrivora had less hormonal activity than neurohypophyses of freshwater amphibians. These findings indicate that the hypothalamopituitary response to dehydration may be less in R. cancrivora than in freshwater amphibians.…”

Section: Introductionmentioning

confidence: 93%

“…Examination ofplasma and pituitary extracts for hydro-osmotic activity The effect of the diluted plasma or pituitary extract in altering the permeability of frog urinary bladder was measured by the method of Dicker & Elliott (19706) using the isolated urinary bladder of R. cancrivora (collected from fresh water). For each measurement a hemibladder was used, a solution consisting of 1 part Ringer and 4 parts water was placed inside it, and the bladder was suspended in aerated Ringer solution or Ringer plus a known amount of the plasma or pituitary extract being examined.…”

Section: Animalsmentioning

confidence: 99%

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Vasotocin-Like Activity in the Plasma of the Euryhaline Frog (Rana Cancrivora) After Transfer From Fresh Water to Saline

Elliott¹,

Chew²

1975

Journal of Endocrinology

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When Rana cancrivora were collected from fresh water and dehydrated (weight loss 4-10%) by exposure to saline, the plasma titre of hydro-osmotic activity, measured by amphibian bladder assay, was increased three-to fourfold. This activity, which was abolished by thioglycollate and by incubation with tyrosinase or trypsin, was ascribed to vasotocin. The plasma vasotocin activities (hydrated and dehydrated frogs respectively) were estimated to be 0-03-0-5 and 0-15-0-25 mug/1; if referred to oxytocin as a standard the equivalent values were 10 and 30-60 mu./ml. Assuming that the increase represented released pituitary hormone, the amount of vasotocin released by osmotic dehydration was calculated to be of the order of 1 ng. Pituitary glands of hydrated and dehydrated frogs were estimated to have 0.15 and 0-18 mug vasotocin/gland respectively. The possible physiological function of released vasotocin in promoting reabsorption of urea from the urinary bladder is discussed in relation to the euryhaline ability of R. cancrivora.

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Section: Introductionmentioning

confidence: 93%

Section: Animalsmentioning

confidence: 99%

Vasotocin-Like Activity in the Plasma of the Euryhaline Frog (Rana Cancrivora) After Transfer From Fresh Water to Saline

Elliott¹,

Chew²

1975

Journal of Endocrinology

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“…1967;Eggena el al., 1968], bladders of R. cancrivora were only slightly more sensitive to oxytocin than to vasopressin. No hydrosrnotic response was shown when either peptide was in concentrations smaller than 10 8 m [D icker and Elliott, 1970c]. The bladder of R. cancrivora was about 1,000 times more sensitive to vasotocin than to the mammalian peptides, but it was still markedly less sensitive than bladders of other anuran amphibians.…”

Section: Bladdermentioning

confidence: 99%

“…C h ew et al [1972] have investigated this problem quite recently. Using essentially the same method of isolated hemi-bladders described by D icker and Elliott [1970c], with Fig. 4.…”

Section: Bladdermentioning

confidence: 99%

“…In even more recent experiments by E llio tt and C h ew [to be published. 1972], these authors, using as test object the isolated bladder of R. cancrivora [D icker and Elliott. 1970c], submitted it to the action of diluted plasma from fresh water R. cancrivora and compared the effect with that produced by plasma from R. cancrivora exposed for 4 h to a NaCI solution of 400 mOsmole/kg H20 .…”

Section: Neurohypophysial Hormonesmentioning

confidence: 99%

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Neurohypophysial Hormones and Homeostasis in the Crab-Eating Frog, Rana cancrivora

Dicker¹,

Elliott²

1973

Horm Res

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Mechanisms of homeostasis in a euryhaline amphibian, Rana cancrivora, the crab-eating frog, are reviewed and discus-sed. While plasma osmolality of R. cancrivora is always greater thanthe bathing fluid (from 0 to 800 mOsmole), urine is always dilutewith reference to plasma. Homeostasis is maintained by the factthat the skin, though permeable to water, is insensitive to the actionof neurohypophysial hormones, the potential differences, short circuit current and net influx of Na+ across it being smaller than inother anuran amphibians. The hypertonicity of the plasma when the frog is in saline solutions is achieved by an increase of plasma NaCl and urea concentration. The mechanism by which plasma urea concentration increases from 40 mM when the frog is in fresh water to 400 mM when in brackish water can be explained by an initial diffusion of urea from the bladder, followed by an enhanced activity of the enzymes of the ornithine-urea cycle. Rapid diffusion of urea into muscles protects the latter against damage due to hypertonicity of the plasma and extracellular fluid. Neurohypophysial hormones appear to act mainly on the bladder where they appear to increase the permeability to urea. The gastrointestinal tract does not play a major role in the mechanism of adaptation to hypertonic solutions. The significance of the different mechanisms used by R. cancrivora to maintain homeostasis are discussed in relation to similar problems in other anuran amphibians.

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Membrane potential measurements during rat liver regeneration

Wondergem

Harder

1980

Journal Cellular Physiology

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Membrane potential was measured in perfused rat liver and was shown to increase from -33 +/- 1.0 mV in livers from normal rats to -50 +/- 1.1 mV in livers from rats 12 hr after partial hepatectomy. The hyperpolarization of the membrane in regenerating liver was no longer evident after perfusion with 1 mM ouabain for 5 min. Ouabain had a small (4 mV) depolarizing effect on membrane potential in normal liver. The potential measured in normal and regenerating liver decreased as a function of the external potassium concentration above 5 mM; however, the potential was more electronegative in regenerating liver compared to normal liver at all values of external potassium concentration, and the differences in potential between the two kinds of cells did not decrease at higher concentrations of external potassium. Thus, a plot of membrane potential vs external potassium concentration resulted in approximately parallel curves for the two different cell types. We conclude that hyperpolarization of the liver cell membrane is an early event during rat liver regeneration and results from an electrogenic Na-K pump.

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Effect of neurohypophysial hormones on fluid movement across isolated bladder of Rana cancrivora, Rana temporaria and Bufo melanostictus

Cited by 21 publications

References 19 publications

Vasotocin-Like Activity in the Plasma of the Euryhaline Frog (Rana Cancrivora) After Transfer From Fresh Water to Saline

Vasotocin-Like Activity in the Plasma of the Euryhaline Frog (Rana Cancrivora) After Transfer From Fresh Water to Saline

Neurohypophysial Hormones and Homeostasis in the Crab-Eating Frog, <i>Rana cancrivor</i><i>a</i>

Membrane potential measurements during rat liver regeneration

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