METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 139-147 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Urine Volume ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level

Male albino rats were fed ad libitum isocaloric diets containing 5%, 20%, and 40% protein and 10% corn oil by weight. Measurements were made of nitrogen retention, urine volume, water intake, body composition, and blood levels of glucose, amino nitrogen, and urea at environmental temperatures of 22 ± 2 °C (7 days) followed by 2 ± 1 °C (8 days). Significant metabolic differences were evident among the three dietary groups at 22 °C but these differences were, in general, reduced under conditions of cold exposure. It is of interest that the rats on the 40% protein diet did not exhibit the typical increases in food consumption and urine volume when exposed to cold and, further, that these animals appeared able to maintain body weight and synthesize body fat during cold exposure. It seems that dietary protein level may play an important role during exposure to cold.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 139-147 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Urine Volume ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level

Male albino rats were fed ad libitum isocaloric diets containing 5%, 20%, and 40% protein and 10% corn oil by weight. Measurements were made of nitrogen retention, urine volume, water intake, body composition, and blood levels of glucose, amino nitrogen, and urea at environmental temperatures of 22 ± 2 °C (7 days) followed by 2 ± 1 °C (8 days). Significant metabolic differences were evident among the three dietary groups at 22 °C but these differences were, in general, reduced under conditions of cold exposure. It is of interest that the rats on the 40% protein diet did not exhibit the typical increases in food consumption and urine volume when exposed to cold and, further, that these animals appeared able to maintain body weight and synthesize body fat during cold exposure. It seems that dietary protein level may play an important role during exposure to cold.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL WITH CALORIC RESTRICTION IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 149-160 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level ◽  
Isocaloric Diets ◽  
Environmental Temperatures

Male albino rats were fed isocaloric diets (5%, 20%, and 40% protein and 10% corn oil by weight) in restricted amounts (6 g/rat per day) at environmental temperatures of 22 °C and 2 °C. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of body contents of protein, moisture, and total crude fatty acids. Metabolic effects of food restriction were readily apparent at 22 °C and the diet appeared to play a role in modifying some of these effects in approximate proportion to the dietary protein level. With superimposition of cold exposure, metabolic differences among groups were decreased in degree with some suggestive evidence of a beneficial effect of increased dietary protein level and of a deleterious effect of decreased dietary protein (high carbohydrate) under these conditions.

METABOLIC EFFECTS OF THREE DIETARY PROTEIN LEVELS FED ISOCALORICALLY TO COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 161-170 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
J. Laufer ◽  
A. Turner
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Beneficial Effects ◽  
Dietary Protein Level ◽  
Environmental Temperatures

Male albino rats were fed isocalorically on diets containing 5%, 20%, and 40% protein (casein) and 10% corn oil by weight at environmental temperatures of 22 °C and 2 °C. Since the 5% protein fed group consumed less than normal amounts of food, consequently the food intake of all groups was moderately restricted. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of total body content of protein, water, and crude fatty acids. Metabolic effects of dietary protein level were readily apparent at both environmental temperatures. Unlike earlier studies with ad libitum and severely restricted feeding, superimposition of cold exposure did not eliminate metabolic differences among groups. As observed in previous studies, reduction of dietary protein level from 20% to 5% had a deleterious effect in cold-exposed rats. In the present study no beneficial effects due to increasing dietary protein level from 20% to 40% were observed.

METABOLIC EFFECTS OF THREE DIETARY PROTEIN LEVELS FED ISOCALORICALLY TO COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 161-170 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
J. Laufer ◽  
A. Turner
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Beneficial Effects ◽  
Dietary Protein Level ◽  
Environmental Temperatures

Male albino rats were fed isocalorically on diets containing 5%, 20%, and 40% protein (casein) and 10% corn oil by weight at environmental temperatures of 22 °C and 2 °C. Since the 5% protein fed group consumed less than normal amounts of food, consequently the food intake of all groups was moderately restricted. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of total body content of protein, water, and crude fatty acids. Metabolic effects of dietary protein level were readily apparent at both environmental temperatures. Unlike earlier studies with ad libitum and severely restricted feeding, superimposition of cold exposure did not eliminate metabolic differences among groups. As observed in previous studies, reduction of dietary protein level from 20% to 5% had a deleterious effect in cold-exposed rats. In the present study no beneficial effects due to increasing dietary protein level from 20% to 40% were observed.

METABOLIC EFFECTS OF DIETARY PROTEIN LEVEL WITH CALORIC RESTRICTION IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 149-160 ◽  
Author(s):  
John R. Beaton ◽  
T. Orme ◽  
A. Turner ◽  
J. Laufer
Keyword(s):  
Dietary Protein ◽  
Protein Level ◽  
Corn Oil ◽  
Amino Nitrogen ◽  
Metabolic Effects ◽  
Albino Rats ◽  
Blood Levels ◽  
Dietary Protein Level ◽  
Isocaloric Diets ◽  
Environmental Temperatures

Male albino rats were fed isocaloric diets (5%, 20%, and 40% protein and 10% corn oil by weight) in restricted amounts (6 g/rat per day) at environmental temperatures of 22 °C and 2 °C. Measurements were made of urinary excretion of nitrogen, potassium, sodium, phosphorus, and creatinine, of blood levels of glucose, urea, amino nitrogen, packed cell volume, and serum total proteins and of body contents of protein, moisture, and total crude fatty acids. Metabolic effects of food restriction were readily apparent at 22 °C and the diet appeared to play a role in modifying some of these effects in approximate proportion to the dietary protein level. With superimposition of cold exposure, metabolic differences among groups were decreased in degree with some suggestive evidence of a beneficial effect of increased dietary protein level and of a deleterious effect of decreased dietary protein (high carbohydrate) under these conditions.

THE RELATION OF DIETARY PROTEIN LEVEL TO LIVER ENZYME ACTIVITIES IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 1871-1877
Author(s):  
John R. Beaton
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Liver Enzymes ◽  
Albino Rats ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Phosphate Activated Glutaminase ◽  
Relationship Of ◽  
Environmental Temperatures

Male, albino rats were fed diets containing 5%, 20%, and 40% casein by weight for 7 days at environmental temperatures of 22 °C and 2–3 °C. In one experiment, food was provided ad libitum; in a second experiment, all groups were provided with equal amounts of food. At 22 °C, the activities in liver of alanine-glutamic transaminase, phosphate-activated glutaminase, and arginase increased with increasing dietary protein level. At 2–3 °C, activities of the last two enzymes increased with increasing dietary protein level from 5% to 20% but not from 20% to 40% whereas transaminase activities increased throughout the dietary protein range 5% to 40%. No relationship of glucose-6-phosphatase activity to dietary protein level was evident at either environmental temperature. Cold exposure per se increased the activities of alanine-glutamic transaminase and glucose-6-phosphatase in all dietary protein groups but increased the activities of arginase and phosphate-activated glutaminase only in rats fed the 5% and 20% protein diets. It is postulated that increased activities of these liver enzymes during cold exposure result from augmented catabolism of substrates to meet increased energy requirements. As previously observed with respect to other metabolic alterations, it is apparent that cold exposure modifies the response of liver enzymes to changing dietary protein levels.

THE RELATION OF DIETARY PROTEIN LEVEL TO LIVER ENZYME ACTIVITIES IN COLD-EXPOSED RATS

1963 ◽  
Vol 41 (9) ◽  
pp. 1871-1877 ◽  
Author(s):  
John R. Beaton
Keyword(s):  
Cold Exposure ◽  
Dietary Protein ◽  
Protein Level ◽  
Liver Enzymes ◽  
Albino Rats ◽  
Protein Levels ◽  
Dietary Protein Level ◽  
Phosphate Activated Glutaminase ◽  
Relationship Of ◽  
Environmental Temperatures

Male, albino rats were fed diets containing 5%, 20%, and 40% casein by weight for 7 days at environmental temperatures of 22 °C and 2–3 °C. In one experiment, food was provided ad libitum; in a second experiment, all groups were provided with equal amounts of food. At 22 °C, the activities in liver of alanine-glutamic transaminase, phosphate-activated glutaminase, and arginase increased with increasing dietary protein level. At 2–3 °C, activities of the last two enzymes increased with increasing dietary protein level from 5% to 20% but not from 20% to 40% whereas transaminase activities increased throughout the dietary protein range 5% to 40%. No relationship of glucose-6-phosphatase activity to dietary protein level was evident at either environmental temperature. Cold exposure per se increased the activities of alanine-glutamic transaminase and glucose-6-phosphatase in all dietary protein groups but increased the activities of arginase and phosphate-activated glutaminase only in rats fed the 5% and 20% protein diets. It is postulated that increased activities of these liver enzymes during cold exposure result from augmented catabolism of substrates to meet increased energy requirements. As previously observed with respect to other metabolic alterations, it is apparent that cold exposure modifies the response of liver enzymes to changing dietary protein levels.

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