The Effects of Posterior Pituitary Extracts on Water Balance in Bufo Carens and Xenopus Laevis, together with some General Considerations of Anuran Water Economy

1952 ◽  
Vol 29 (3) ◽  
pp. 429-439
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Xenopus Laevis ◽  
Water Uptake ◽  
Seasonal Variations ◽  
Biological Significance ◽  
Weight Increase ◽  
Posterior Pituitary ◽  
Large Weight ◽  
Water Economy ◽  
Diuretic Response

1. The effects of pitressin and pitocin on water balance in Bufo carens and Xenopus laevis have been investigated. Bufo carens is most sensitive to pitressin, and shows an increased water uptake together with a well-marked anti-diuretic response. Xenopus reacts equally to the two extracts by an increase in water uptake, but there is no anti-diuresis. 2. The effects of pitressin and pitocin in causing lymph accumulation and resorbtion of fluid from the bladder have been studied in Bufo regularis. Pitressin has the greater effect, and there are indications of seasonal variations in the magnitude of the response. 3. The normal rates of water uptake of B. regularis, B. carens and Xenopus laevis have been measured. The two species of Bufo take up water rapidly, but Xenopus does so much more slowly. After desiccation the water uptake of Bufo regularis increases very considerably. This does not occur in Xenopus. 4. There is a large weight increase after injection of posterior pituitary extracts in Bufo regularis and B. carens, but not in Xenopus laevis. The findings of other workers on the magnitude of the weight increase after posterior pituitary injections are summarized. 5. The results are discussed in relation to the identity of the active principles of the anuran posterior pituitary and to the biological significance of the responses.

The Effect of Pituitrin Injection on the Water Balance of Bufo Regularis Reuss

1950 ◽  
Vol 27 (1) ◽  
pp. 40-49
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Water Content ◽  
Water Uptake ◽  
Lymphatic System ◽  
Biological Significance ◽  
Body Water ◽  
Urine Flow ◽  
The Body ◽  
Excess Water

1. A method of cannulating the cloaca of Anura is described. 2. Using this method it is found that in Bufo regularis the increase in body water which follows pituitrin injection is the result of an increased rate of water uptake, together with a diminished urine flow. 3. The excess water is mostly retained in the lymph spaces, while the water content of the tissues of the body increases very little. 4. The bearing of these results on the problem of the identification of the substance or substances which elicit the amphibian water balance effect, and the biological significance of the organization of the anuran lymphatic system are discussed.

scholarly journals The Effect of Pitressin and Pitocin on Water Balance in Bufo Regularis Reuss

1951 ◽  
Vol 28 (3) ◽  
pp. 374-384
Author(s):  
R. F. EWER
Keyword(s):  
Water Balance ◽  
Water Absorption ◽  
Water Uptake ◽  
Marked Decrease ◽  
Urine Flow ◽  
Diuretic Effect ◽  
Posterior Pituitary ◽  
Antagonistic Action ◽  
Diuretic Action ◽  
Main Factor

1. In Bufo regularis the injection of either pitressin or pitocin is followed by an increase in the rate of water absorption through the skin, together with a marked decrease in urine flow. The response to pitressin is greater than that to pitocin. 2. The effect of pitocin in increasing water uptake can be attributed to the activity of the 5-10% of the pressor fraction which it contains. 3. A mixture of pitressin and pitocin has the same effect on water balance as a corresponding dose of pituitrin. Pitressin alone has a greater anti-diuretic effect than it has when pitocin is added. 4. Taking into account the antagonistic action of pitocin to pitressin it is possible to account for the anti-diuretic action of pitocin in terms of its pressor fraction content. 5. It is concluded that the pressor fraction is the main factor responsible for both the dermal and the renal components of the water-balance effect produced in B. regularis by injection of mammalian posterior pituitary extracts. This conclusion is discussed in relation to the findings of other workers.

Water Uptake and Moulting in Bufo Regularis Reuss

1951 ◽  
Vol 28 (3) ◽  
pp. 369-373 ◽  
Author(s):  
R. F. EWER
Keyword(s):  
Water Uptake ◽  
Urine Flow ◽  
Posterior Pituitary

1. In Bufo regularis Reuss moulting is accompanied by an increase in the rate of water uptake through the skin. An increase in urine flow is also observed, starting some time after the rate of water uptake has begun to increase. 2. No increase in rate of water uptake occurs following thyroxine feeding on 4 successive days. 3. The possibility that posterior pituitary activity is responsible for the observed increase in rate of water uptake during moulting is discussed.

Factors Influencing Diuresis in Rats Following Total-Body X-Irradiation

1957 ◽  
Vol 189 (1) ◽  
pp. 11-14 ◽  
Author(s):  
E. Irene Pentz ◽  
Robert J. Hasterlik
Keyword(s):  
Adrenal Cortex ◽  
Anterior Pituitary ◽  
Adrenal Glands ◽  
Anterior Lobe ◽  
Posterior Pituitary ◽  
Cortical Control ◽  
Factors Influencing ◽  
X Irradiation ◽  
Diuretic Response ◽  
Total Body

An immediate diuresis has been observed in rats exposed to total-body x-irradiation ranging between 100 and 400 r. Since the highest dosage produced more consistent results, it was used in conjunction with extirpation of various glands and other organs in an effort to determine the mechanism that responds so promptly to x-irradiation. The anterior pituitary and the adrenal cortex are of prime importance in this reaction. Removal of the anterior lobe of the pituitary or removal of the adrenal glands is sufficient to completely inhibit diuresis following 400 r x-irradiation. This diuretic response is not dependent upon the presence of the posterior pituitary since animals having only this gland removed became diuretic following exposure to 400 r. The evidence suggests that the release of antidiuretic substances from tissues other than the posterior pituitary is under anterior pituitary-adrenal cortical control.

scholarly journals The isolation of three neurophysins from porcine posterior pituitary lobes

1970 ◽  
Vol 116 (5) ◽  
pp. 899-909 ◽  
Author(s):  
L. O. Uttenthal ◽  
D. B. Hope
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Gel Filtration ◽  
Biological Significance ◽  
Starch Gel Electrophoresis ◽  
Posterior Pituitary ◽  
Fresh Tissue ◽  
Molecular Weights ◽  
Molecular Dimensions

1. Three neurophysins, proteins that bind the polypeptide hormones oxytocin and vasopressin, have been isolated from acetone-dried porcine posterior pituitary lobes. The proteins have been named porcine neurophysins-I, -II and -III in order of their electrophoretic mobilities at pH8.1. 2. Electrophoretic comparison of the purified proteins, which are homogeneous on starch-gel electrophoresis, with the soluble proteins of fresh porcine posterior pituitary lobes extracted in 0.1m-HCl and in buffer pH8.1 suggests that the isolated proteins are native to the fresh tissue. 3. Neurophysins-I and -II are present in similar amounts in the tissue, whereas neurophysin-III is present only in small quantities. Acetone-dried tissue also contains traces of other hormone-binding neurophysin components. 4. All the neurophysins can bind both oxytocin and [8-lysine]-vasopressin. 5. The apparent molecular weights of the neurophysins increase with increasing protein concentration as measured by equilibrium sedimentation in the ultracentrifuge. 6. Neurophysins-I and -III are of similar molecular dimensions, contain one residue of methionine per molecule and lack histidine. The minimum molecular weight of neurophysin-I obtained by amino acid analysis is 9360. Neurophysin-II is of larger molecular dimensions than neurophysins-I and -III and can be separated from these by gel filtration on Sephadex G-75. It contains no histidine or methionine, and its minimum molecular weight has been estimated as 14020 by amino acid analysis. 7. Each of the three neurophysins possesses N-terminal alanine. 8. The possible biological significance of the existence of several neurophysins within one species is discussed.

scholarly journals Rain Cracking in Sweet Cherries is not Due to Excess Water Uptake but to Localized Skin Phenomena

2016 ◽  
Vol 141 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Andreas Winkler ◽  
Stefanie Peschel ◽  
Kathleen Kohrs ◽  
Moritz Knoche
Keyword(s):  
Water Balance ◽  
Water Uptake ◽  
Prunus Avium ◽  
Fruit Cracking ◽  
Excess Water ◽  
Fruit Skin ◽  
Sweet Cherries ◽  
Local Exposure ◽  
Skin Wetness ◽  
Phase Water

Rain cracking of sweet cherry (Prunus avium L.) fruit is commonly thought to result from excessive net water uptake. This excess increases flesh turgor, which then strains and eventually ruptures the skin at the weakest point. This idea—the critical turgor hypothesis—assumes the fruit comprises a semifluid flesh, held under pressure by a taut skin. The objectives of this study were to test the validity of this popular hypothesis. We investigated the effects of 1) the different pathways of water uptake and 2) the fruit’s water balance on cracking. Incubating fruit of 19 cultivars in water resulted in rapid fruit cracking. The time to 50% cracking (T50) averaged 7.5 ± 1.3 hours with considerable variability between cultivars (T50 range from 1.5 to 18.6 hours). The amount of water taken up at 50% cracking (WU50) averaged 96.5 ± 17.6 mg (WU50 range from 17.7 to 331.5 mg). There was no correlation between either the T50 or the WU50, and the rate of water uptake. Also, there was no correlation between the values of T50 (r = 0.58) and only a weak correlation between the values of WU50 (r = 0.80*) determined in different years. Comparing the value of WU50 under incubation vs. under perfusion revealed a 3.9- to 38-fold higher WU50 under perfusion (397.6 to 1840 mg) than under incubation (48.8 to 102.6 mg). This marked dissimilarity remained, regardless of pretreatments with isotonic polyethylene glycol (PEG) 6000 to induce microcracking or by manipulation of skin wetness during perfusion. Sealing the pedicel/fruit junction markedly decreased the rate of water uptake under incubation. It had no effect on the T50, and it markedly decreased the WU50. Similarly, manually induced skin defects greatly increased the rate of water uptake but, with few exceptions, had no effect on the T50, whereas, the WU50 had increased. The location on the fruit surface of the resulting cracks was not related to the region of the skin in which the manual defect was induced. Allowing the fruit to transpire increased both, the T50 and the WU50. Interestingly, the amount of water lost by transpiration exceeded the amount that was subsequently required to cause cracking up to 5-fold. Incubating fruit with their stylar ends immersed in water, whereas their remaining surfaces were in air of 0%, 28%, 75%, or 100% relative humidity (RH) resulted in net losses of water of up to 5.9 ± 0.7 mg·h−1, nevertheless their stylar ends still cracked. All our results indicate rain cracking in sweet cherries is a localized phenomenon that is not related to the net fruit water balance (the critical turgor hypothesis) but is the result of more local exposure of the fruit skin to liquid-phase water (the zipper hypothesis).

scholarly journals Cellular and Subcellular Evidence for Neuronal Interaction between the Chemokine Stromal Cell-Derived Factor-1/CXCL 12 and Vasopressin: Regulation in the Hypothalamo-Neurohypophysial System of the Brattleboro Rats

Endocrinology ◽  
2007 ◽  
Vol 149 (1) ◽  
pp. 310-319 ◽  
Author(s):  
Céline Callewaere ◽  
Brigitte Fernette ◽  
Danièle Raison ◽  
Patricia Mechighel ◽  
Arlette Burlet ◽  
...  
Keyword(s):  
Water Balance ◽  
Paraventricular Nucleus ◽  
Stromal Cell ◽  
Neuronal Cell ◽  
Original Data ◽  
Brattleboro Rats ◽  
Posterior Pituitary ◽  
Electrophysiological Properties ◽  
Chronic Infusion ◽  
Stromal Cell Derived Factor

We previously described a colocalization between arginine vasopressin (AVP) and the chemokine stromal cell-derived factor-1α (SDF-1) in the magnocellular neurons of both the hypothalamic supraoptic and paraventricular nucleus as well as the posterior pituitary. SDF-1 physiologically affects the electrophysiological properties of AVP neurons and consequently AVP release. In the present study, we confirm by confocal and electron microscopy that AVP and SDF-1 have a similar cellular distribution inside the neuronal cell and can be found in dense core vesicles in the nerve terminals in the posterior pituitary. Because the Brattleboro rats represent a good model of AVP deficiency, we tested in these animals the fate of SDF-1 and its receptor CXCR4. We identified by immunohistochemistry that both SDF-1 and CXCR4 immunoreactivity were strongly decreased in Brattleboro rats and were strictly correlated with the expression of AVP protein in supraoptic nucleus, paraventricular nucleus, and the posterior pituitary. We observed by real-time PCR an increase in SDF-1 mRNA in both heterozygous and homozygous rats. The effect on the SDF-1/CXCR4 system was not linked to peripheral modifications of kidney water balance because it could not be restored by chronic infusion of deamino-8D-ariginine-vasopressin, an AVP V2-receptor agonist. These original data further suggest that SDF-1 may play an essential role in the regulation of water balance.

Sign in / Sign up

Export Citation Format

Share Document