Effect of water restriction on urinary concentrating ability of K-depleted rats

1960 ◽  
Vol 199 (5) ◽  
pp. 912-914 ◽  
Author(s):  
William B. Blythe ◽  
Margaret Newton ◽  
Fernando Lazcano ◽  
Louis G. Welt
Keyword(s):  
Water Intake ◽  
The Other ◽  
Potassium Depletion ◽  
Water Restriction ◽  
Control Groups ◽  
Ad Libitum ◽  
Urinary Concentrating Ability ◽  
Excessive Water ◽  
Urine Concentrating Ability ◽  
Concentrating Defect

In order to test the possibility that the urinary concentrating defect associated with potassium depletion results from excessive water intake that accompanies potassium depletion, water intake was restricted in one half of a group of rats undergoing potassium depletion. The other one half of the group was allowed to drink ad libitum After 14 days, ability to concentrate the urine was tested in both groups as well as in two groups of control rats, one of which was allowed to drink ad libitum and the other having water intake restricted. Although both potassium-depleted groups concentrated urine less than the control groups, there was no difference in urine-concentrating ability between the two potassium-depleted groups. It is concluded that the urinary concentrating defect in potassium depletion is not due to excessive water intake.

Value of fluid and electrolyte supplements in subarctic survival situations

1964 ◽  
Vol 19 (4) ◽  
pp. 580-582 ◽  
Author(s):  
Terence A. Rogers ◽  
James A. Setliff
Keyword(s):  
Water Intake ◽  
Fluid Balance ◽  
Cold Exposure ◽  
High Water ◽  
The Other ◽  
Standard Diet ◽  
High Water Intake ◽  
Ad Libitum

After 48 hr on a standard diet indoors, 30 men were subjected to cold and starvation in the winter subarctic. During the fast, ten men got 230 mEq NaCl each, ten got 115 mEq NaCl plus 115 mEq NaHCO3, and the other ten got a placebo. Of each group of ten, five had water ad libitum and the other five each had a “forced” intake of 1,920 ml. In each electrolyte-supplemented group, those with the high water intake dehydrated to the same extent as those drinking ad libitum. Those getting NaCl or NaCl plus NaHCO3 lost a mean of about 1 kg less weight than those in the placebo groups. The NaHCO3 did not diminish the fasting acidosis. cold exposure; fasting; fluid balance; starvation Submitted on January 22, 1964

Body temperature responses to exercise in man on restricted food and water intake

1959 ◽  
Vol 14 (2) ◽  
pp. 194-198 ◽  
Author(s):  
F. Grande ◽  
J. E. Monagle ◽  
E. R. Buskirk ◽  
H. L. Taylor
Keyword(s):  
Water Intake ◽  
Sweat Rate ◽  
Control Level ◽  
High Water ◽  
Progressive Increase ◽  
Important Change ◽  
Water Restriction ◽  
Water Group ◽  
Adequate Food ◽  
Ad Libitum

Rectal temperatures (TR) of 12 clinically healthy soldiers were measured in a room at 25.5°C and 40–45% relative humidity during a 1-hour walk on a motor driven treadmill at 3.5 mph and 10% grade, during control with adequate food intake and water ad libitum, and during a period of food and water restriction. The daily water intake during the water restriction period was 900 ml for six of the men, Low Water group (L.W.), and 1800 ml for the other six, High Water group (H.W.). The restriction of water began at the same time as the restriction of food and lasted 5 full days for the L.W. group and 10 full days for the H.W. group. Food was restricted to 1000 calories from carbohydrate, 4.5 gm of NaCl and a multivitamin pill/day for 16 days. Water ad libitum was given throughout the experiment except for the period of water restriction. The L.W. group showed a progressive increase of TR at the end of the walk during the water restriction period with average TR 1.51℃, higher at peak dehydration than in control. In the H.W. group the greatest average increase, 0.46℃, was observed on day 5 of restriction. Administration of water ad libitum brought the work TR back to the control level in the L.W. group, but failed to produce any important change in the H.W. group. The relationship between dehydration, elevation of TR during work and changes in sweat rate is discussed. Submitted on July 24, 1958

Impairment in fluid ingestion in rats with lesions of the zona incerta

1977 ◽  
Vol 233 (1) ◽  
pp. R53-R58 ◽  
Author(s):  
M. D. Evered ◽  
G. J. Mogenson
Keyword(s):  
Water Intake ◽  
Water Deprivation ◽  
Zona Incerta ◽  
Subsequent Reduction ◽  
Fluid Ingestion ◽  
Daily Water Intake ◽  
Daily Water ◽  
Ad Libitum ◽  
The Brain ◽  
Excessive Water

Rats with lesions of the zona incerta (ZI) dorsal to the lateral hypothalamus drink as much water as controls following intracellular or extracellular dehydration but restrict their daily water intake to minimal requirements for fluid balance, suggesting a specific impairment in secondary drinking. Following water deprivation, however, rats with ZI lesions responded to changes in palatability of the water as if they were experiencing slightly greater difficulty or aversiveness in drinking than controls. The cause appears to be an impairment in the ability to lick fluids from a spout. When water was available ad libitum or when water or liquid diet were provided after water or food deprivation, rats with ZI damage were unable to obtain as much fluid per lick as controls. It is concluded that lesions in this region of the brain impair the motor act of drinking and that the subsequent reduction in the efficiency of drinking is the cause of the attenuation of excessive water intake.

Hypotensive effect of water restriction in the two-kidney one-clip hypertensive rat

1981 ◽  
Vol 241 (5) ◽  
pp. F525-F531
Author(s):  
F. H. Leenen ◽  
W. de Jong
Keyword(s):  
Blood Pressure ◽  
Water Intake ◽  
Hypotensive Effect ◽  
Free Access ◽  
Water Restriction ◽  
Hypertensive Rats ◽  
Effect Of Water ◽  
Hypertensive Rat ◽  
Access To Water ◽  
Ad Libitum

In two-kidney one-clip hypertensive rats we evaluated the effect of water restriction on the development and maintenance of severe hypertension (systemic blood pressure 200-230 mmHg). After application of renal arterial clips in rats allowed access to water for 1 or 2 h daily, BP stabilized at 180-190 mmHg. No increase in water intake occurred and plasma renin activity(PRA) (measured before the drinking period) was significantly below the levels observed in ad libitum-drinking hypertensive rats. In rats administered 4 ml water/100 g body weight twice daily by gavage, development of hypertension was more clearly suppressed. Blood pressure increased slowly and reached levels of only 150-170 mmHg. Furthermore, PRA was significantly lower in this group compared with ad libitum-drinking hypertensive animals. In rats with established (4-5 wk) renal hypertension, restriction of water intake to 1 or 2 h daily resulted in a rapid decrease in BP of about 30 mmHg. Daily administration of Pitressin tannate to hypertensive rats allowed free access to water induced a similar decrease in BP as well as suppression of PRA. These results indicate that the hypotensive effect of water restriction in the two-kidney one-clip hypertensive rat model may be mediated, at least in part, through elevated circulating levels of vasopressin that subsequently inhibit renin release.

Polyuria and imparied ADH release following medial preoptic lesioning in the rat

1975 ◽  
Vol 228 (5) ◽  
pp. 1293-1297 ◽  
Author(s):  
M van Gemert ◽  
M Miller ◽  
RJ Carey ◽  
AM Moses
Keyword(s):  
Water Intake ◽  
Fluid Intake ◽  
Plasma Osmolality ◽  
Histological Evidence ◽  
Impaired Ability ◽  
Access To Water ◽  
The Central Nervous System ◽  
Ad Libitum ◽  
Urine Concentrating Ability ◽  
Supraoptic Nuclei

Studies were carried out in the rat to detemine if hypothalamic lesions which caused polydipsia and polyuria had their effect mediated through an alteration of the ability of the neurohypophyseal system to release ADH. Rats with medial preoptic lesions hadincreased water intake while on ad libitum access to water and slightly impaired ability to conserve water following dehydration, but with no impairment of urine-concentrating ability. These were associated with an increase in plasma osmolality both during ad libitum fluid intake and after dehydration. Urinary ADH excretion was at leastas great as in shamoperated controls during ad libitum water intake, but failed to increase during dehydration in spite of a marked increase in plasma osmolality. Pituitary ADH content did not differ from control animals either during ad libitum water intake of after dehydration. Animals with lesions in the lateral preoptic and septal areas did not differ from control animals during ad libitum fluid intake and after dehydration even though lateral preoptic lesions produced polydipsia. In all animals, lesions were remote from the supraoptic nuclei, which showed no histological evidence of damage. It is concluded thatareas of the central nervous system away from the supraoptic nuclei are involved in the regulation of both water intake and ADH release.

Prostaglandins and the urinary concentrating defect in potassium-depleted rabbits

1987 ◽  
Vol 253 (6) ◽  
pp. F1113-F1119 ◽  
Author(s):  
K. H. Raymond ◽  
M. D. Lifschitz ◽  
T. D. McKinney
Keyword(s):  
Prostaglandin E ◽  
Potassium Depletion ◽  
Guanine Nucleotide ◽  
Urinary Osmolality ◽  
New Zealand White Rabbits ◽  
Ad Libitum ◽  
Collecting Tubules ◽  
Concentrating Defect

Urinary prostaglandin E (UPGE) excretion increased significantly after 1 and 2 wk of potassium depletion (KD) in female New Zealand White rabbits on ad libitum water intake [UPGE control, 21.3 +/- 4.6 ng PGE/mg creatinine; 1 wk KD, 40.4 +/- 6.1 ng PGE/mg creatinine (P less than 0.01); 2 wk KD, 31.9 +/- 14.9 ng PGE/mg creatinine (P less than 0.05)]. In vivo prostaglandin inhibition with indomethacin or meclofenamate significantly increased urinary osmolality after 12 h of dehydration and exogenous vasopressin (1.25 U) from 794 +/- 59 to 1,163 +/- 113 mosmol/kgH2O (P less than 0.01). In vitro prostaglandin inhibition with indomethacin or meclofenamate corrected the antidiuretic hormone (ADH) unresponsiveness of isolated perfused cortical collecting tubules (CCTs) from KD rabbits. Furthermore, preincubation with pertussis toxin, an agent that inactivates the guanine nucleotide inhibitory (Ni) subunit of adenylate cyclase, normalized the ADH response of KD CCTs, suggesting that prostaglandins may attenuate ADH action on the CCT through activation of Ni and contribute to the urinary concentrating defect associated with KD.

Aorta and Smooth Muscle Electrolytes During Early and Late Hypertension

1957 ◽  
Vol 190 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Edwin E. Daniel ◽  
Oswald Dawkins
Keyword(s):  
Smooth Muscle ◽  
Psoas Muscle ◽  
Sodium Concentration ◽  
The Other ◽  
Stomach Muscle ◽  
Chronic Hypertension ◽  
Potassium Depletion ◽  
Distribution Characteristic ◽  
Control Groups ◽  
Long Duration

Tissue electrolytes in the early phase of hypertension initiated by DCA have been compared with those in later persistent hypertension. In smooth muscle (aorta and stomach muscle) significant potassium depletion occurs during early hypertension in comparison with tissues from treated normotensive animals. A tendency for increased sodium concentration also developed. However, no significant changes from normotensive controls could be demonstrated in aorta during post-DCA, renal or spontaneous hypertension of long duration. These results suggest that there are differences in the disturbances in vascular smooth muscle electrolytes accompanying early and late hypertension. Differences in age or composition of the control groups and in the degree of hypertension produced may explain differences between these results and those of previous workers. None of the other tissues analyzed (left ventricle and psoas muscle) showed changes in electrolyte distribution characteristic of chronic hypertension.

276 Relationship Between Water Use Efficiency and Feedlot Steer Performance and Health

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 142-142
Author(s):  
Kelsey Bruno ◽  
Cashley Ahlberg-Smith ◽  
Levi J McPhillips ◽  
Heather Meador ◽  
Alex Taylor ◽  
...  
Keyword(s):  
Body Weight ◽  
Water Use Efficiency ◽  
Water Use ◽  
Water Intake ◽  
Water Restriction ◽  
Cell Counts ◽  
Health Differences ◽  
Use Efficiency ◽  
Ad Libitum ◽  
Step Down

Abstract As climate change progresses, it is expected that water availability for livestock production will be challenged due to competition from human population growth and use by other agricultural sectors. The objective of this study was to evaluate differences in animal performance and health between feedlot steers with differing water use efficiencies. Four groups of steers from numerous sources (n = 469) were randomly allocated to 2 body weight (BW) blocks. Individual feed and water intake (WI) were measured daily using an Insentec RIC feeding system. Steers had ad libitum access to feed and water for 70 d (BAS). After a 28 d step-down period, steers were maintained at 50% of ad libitum water consumption for 42 d (RST) while feed continued to be offered ad libitum. Based on average daily water intake during BAS, steers were sorted into low, medium, or high-water use efficiency (LWE, MWE, or HWE) using k-means clustering. Every 14 d BW was collected in addition to blood samples for complete blood counts. Body weight was used to evaluate ADG and G:F. Data were analyzed using the GLIMMIX procedure of SAS with the model statement including effects of water use efficiency, day, and the interaction. Body weights were greater in HWE than MWE and LWE at the end of BAS and RST (P < 0.01). Steer ADG and G:F were greater in HWE compared to MWE and LWE (P < 0.01)during BAS, but not different during RST (P > 0.54). Hematocrit and red blood cell counts initially increased during water restriction step down, and then returned to normal levels (P < 0.01); these values were also greater in HWE compared to MWE and LWE (P < 0.01). All steers adapted to limited water access similarly and the degree of health differences had little clinical significance.

Effect of level of water intake on water, energy and nitrogen balance and thyroxine secretion in sheep and goats

1983 ◽  
Vol 34 (4) ◽  
pp. 441 ◽  
Author(s):  
T More ◽  
B Howard ◽  
BD Siebert
Keyword(s):  
Energy Intake ◽  
Water Intake ◽  
Feed Intake ◽  
Nitrogen Balance ◽  
Urine Volume ◽  
Secretion Rate ◽  
Water Restriction ◽  
Sheep And Goats ◽  
Additional Water ◽  
Ad Libitum

Sheep and goats fed on a diet of oaten chaff were subjected to a 50% reduction and a 50-70% increase in their water intake. Measurements were made of water, energy and nitrogen balance and thyroxine secretion rate. Water restriction decreased feed intake by 25%, but in a lesser proportion than expected from the ad libitum feed to water relationship. This effect was achieved by a reduction in the concentration of water in faeces and by the evaporation of less water. When additional water was given, there was a 10% reduction in feed intake associated with a loss of nitrogen brought about by an increase in urine volume. Again less water was evaporated than expected under this treatment. Thyroxine secretion rate was positively related to energy intake.

scholarly journals Using historical data to facilitate clinical prevention trials in Alzheimer disease? An analysis of longitudinal MCI (mild cognitive impairment) data sets

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Manfred Berres ◽  
Andreas U. Monsch ◽  
René Spiegel
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Performance ◽  
Placebo Treatment ◽  
Drug Trial ◽  
The Other ◽  
Data Sets ◽  
Control Groups ◽  
Community Needs ◽  
Clinical Prevention

Abstract Background The Placebo Group Simulation Approach (PGSA) aims at partially replacing randomized placebo-controlled trials (RPCTs), making use of data from historical control groups in order to decrease the needed number of study participants exposed to lengthy placebo treatment. PGSA algorithms to create virtual control groups were originally derived from mild cognitive impairment (MCI) data of the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. To produce more generalizable algorithms, we aimed to compile five different MCI databases in a heuristic manner to create a “standard control algorithm” for use in future clinical trials. Methods We compared data from two North American cohort studies (n=395 and 4328, respectively), one company-sponsored international clinical drug trial (n=831) and two convenience patient samples, one from Germany (n=726), and one from Switzerland (n=1558). Results Despite differences between the five MCI samples regarding inclusion and exclusion criteria, their baseline demographic and cognitive performance data varied less than expected. However, the five samples differed markedly with regard to their subsequent cognitive performance and clinical development: (1) MCI patients from the drug trial did not deteriorate on verbal fluency over 3 years, whereas patients in the other samples did; (2) relatively few patients from the drug trial progressed from MCI to dementia (about 10% after 4 years), in contrast to the other four samples with progression rates over 30%. Conclusion Conventional MCI criteria were insufficient to allow for the creation of well-defined and internationally comparable samples of MCI patients. More recently published criteria for MCI or “MCI due to AD” are unlikely to remedy this situation. The Alzheimer scientific community needs to agree on a standard set of neuropsychological tests including appropriate selection criteria to make MCI a scientifically more useful concept. Patient data from different sources would then be comparable, and the scientific merits of algorithm-based study designs such as the PGSA could be properly assessed.

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