Urea and inulin clearances in undisturbed, unanesthetized rats

Inulin and urea clearances were determined simultaneously on unanesthetized, undisturbed rats with catheters permanently inserted in the abdominal aorta, jugular vein, and urinary bladder. The rats were fed a) a normal Purina chow diet; b) a high-protein diet with normal salt content; or c) a high-protein diet with 2% NaCl added. Some rats on the high-protein, high-salt diet were given additional infusions of either urea or 5% amino acid solution. In the control animals, inulin clearances averaged 0.59 ml/min per 100 g body wt, and urea clearances averaged 0.39 ml/min per 100 g body wt. Significantly higher urea and inulin clearances were obtained on the other diets. Of 79 clearances determined on normal rats given the high-protein, high-salt diet, a total of 17 urea-to-inulin clearance ratios greater than one were obtained No urea-to-inulin clearance ratios greater than one were obtained with any of the other diets. Reasons are given in support of urea production or active secretion by the kidneys as the probable explanations for these results.

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Rag1-null Dahl SS rats reveal that adaptive immune mechanisms exacerbate high protein-induced hypertension and renal injury

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00201.2017 ◽

2018 ◽

Vol 315 (1) ◽

pp. R28-R35 ◽

Cited By ~ 15

Author(s):

Justine M. Abais-Battad ◽

Hayley Lund ◽

Daniel J. Fehrenbach ◽

John Henry Dasinger ◽

David L. Mattson

Keyword(s):

B Lymphocytes ◽

Dietary Protein ◽

High Protein Diet ◽

High Salt ◽

High Protein ◽

Protein Diet ◽

High Salt Diet ◽

Salt Diet ◽

Adaptive Immune ◽

Induced Hypertension

The present study, performed in Dahl salt-sensitive (SS) and SS- Rag1−/− rats lacking T and B lymphocytes, tested the hypothesis that immune cells amplify salt-sensitive hypertension and kidney damage in response to a high-protein diet. After being weaned, SS and SS- Rag1−/− rats were placed on an isocaloric, 0.4% NaCl diet containing normal (18%) or high (30%) protein. At 9 wk of age, rats were switched to a 4.0% NaCl diet containing the same amount of dietary protein and maintained on the high-salt diet for 3 wk. After being fed the high-salt diet, SS rats fed high protein had amplified hypertension and albumin excretion (158.7 ± 2.6 mmHg and 140.8 ± 16.0 mg/day, respectively, means ± SE) compared with SS rats fed normal protein (139.4 ± 3.6 mmHg and 69.4 ± 11.3 mg/day). When compared with the SS rats, SS- Rag1−/− rats fed high protein were protected from exacerbated hypertension and albuminuria (142.9 ± 5.8 mmHg and 66.2 ± 10.8 mg/day). After 3 wk of the high-salt diet, there was a corresponding increase in total leukocyte infiltration (CD45+) in the kidneys of both strains fed high-protein diet. The SS- Rag1−/− rats fed high-protein diet had 74–86% fewer CD3+ T lymphocytes and CD45R+ B lymphocytes infiltrating the kidney versus SS rats, but there was no difference in the infiltration of CD11b/c+ monocytes and macrophages, suggesting that the protective effects observed in the SS- Rag1−/− rats are specific to the reduction of lymphocytes. With the SS- Rag1−/− rats utilized as a novel tool to explore the effects of lymphocyte deficiency, these results provide evidence that adaptive immune mechanisms contribute to the exacerbation of salt-induced hypertension and renal injury mediated by increased dietary protein intake.

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The effect of plane of nutrition on the body composition of two breeds of wearier sheep fed a high protein diet

The Journal of Agricultural Science ◽

10.1017/s0021859600041770 ◽

1982 ◽

Vol 98 (2) ◽

pp. 241-245 ◽

Cited By ~ 21

Author(s):

T. W. Searle ◽

N. McC. Graham ◽

J. B. Donnelly

Keyword(s):

Body Weight ◽

Live Weight ◽

High Protein Diet ◽

The Body ◽

High Protein ◽

The Other ◽

Protein Diet ◽

Castrate Male ◽

Body Component ◽

The Relationship

SUMMARYCorriedale and Dorset Horn castrate male (wether) lambs reared at pasture were weaned at 19 kg live weight (LW), brought indoors and fed a high protein diet such that half of each group grew at ca. 200 g/day and the other half at ca. 100 g/day. Animals were slaughtered at 25 and 30 kg LW and chemical composition (protein, fat, energy, water and ash) of the body determined. The relationship between each body component and shorn empty-body weight was examined by regression analysis.Within levels of feeding the results were similar in the two breeds. When comparisons were made between feeding levels, the slower-growing animals contained more fat, energy and ash than the faster-growing group, less water, but similar amounts of protein at any given empty-body weight.

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Effects of different feeding regimes during lay of egg-type pullets fed either high or low-protein diet during rearing

Australian Journal of Experimental Agriculture ◽

10.1071/ea9780675 ◽

1978 ◽

Vol 18 (94) ◽

pp. 675 ◽

Cited By ~ 1

Author(s):

S Abu-Serewa

Keyword(s):

G Protein ◽

Egg Production ◽

Average Rate ◽

High Protein Diet ◽

High Protein ◽

The Other ◽

Protein Diet ◽

Low Protein Diet ◽

Low Protein ◽

Feeding Regimes

The performance of two groups of pullets reared on either high or low-protein diets was compared under six feeding regimes from 20 to 68 weeks of age. Pullets fed the low-protein (10 per cent) diet from 4 to 20 weeks ate about 20 per cent less food during rearing, were significantly lighter at 20 weeks and were delayed in attaining maturity compared with pullets reared on the high-protein diet. In the period from 20 to 36 weeks of age, pullets reared on the high protein diet laid at a higher rate when fed a laying diet containing 17 per cent protein than with a diet containing 15 per cent protein supplemented with methionine, or 13 per cent protein supplemented with methionine and lysine to the N.R.C. (1971) levels. In contrast, pullets reared on the low-protein diet laid fewer eggs on the 17 per cent protein diet than on the other two diets during the same period. However, no significant rearing x laying interaction was observed in average rate of lay during the whole laying year. The low-protein group laid fewer eggs from 20 to 68 weeks than the other group of birds, but the difference in production was not significant when calculated from maturity. Average rate of lay was not affected by the level of protein in the laying diet, but egg size tended to increase with increasing the level of protein. Increasing the level of protein gradually with the advance in lay had no effect on performance relative to birds fed the 15 or 17 per cent protein diet throughout lay. Restricting the feed intake during lay to 94 per cent of that consumed by full-fed controls, or restricting the time of feeding to four hours daily, reduced egg production by 7 and 6 per cent respectively, regardless of the rearing treatment. Rate of mortality throughout the experiment was not affected by any of the rearing or laying treatments. The results of this experiment indicate that the requirement during lay of pullets reared on a low-protein diet is between 51 and 53 g protein and 900 and 1000 mg of methionine per 4.1 9 MJ (1000 Kcal) ME. This protein concentration should be increased to between 58 and 60 g protein per 4.19 MJ ME if the pullets were reared on conventional diets. Restricting feeding during lay by either of the methods used in this experiment is detrimental to egg production.

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EFFECTS OF CHRONIC EXCESS SALT INGESTION

Journal of Experimental Medicine ◽

10.1084/jem.115.6.1173 ◽

1962 ◽

Vol 115 (6) ◽

pp. 1173-1190 ◽

Cited By ~ 435

Author(s):

Lewis K. Dahl ◽

Martha Heine ◽

Lorraine Tassinari

Keyword(s):

Genetic Factors ◽

High Salt ◽

The Other ◽

Experimental Hypertension ◽

Sprague Dawley ◽

High Salt Diet ◽

Salt Diet ◽

Sprague Dawley Rats ◽

Genetic Technique

Using the genetic technique of selective inbreeding, it has been possible to quickly develop two statistically separable populations from one unselected strain of Sprague-Dawley rats. One of these is very sensitive, the other very resistant, to the development of experimental hypertension from a high salt diet. It was suggested that similar genetic factors operate in man.

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