Influence of Different Types of Malnutrition on the 14C-Lysine Metabolism in Young Rats

Schreier, K; Kazassis, Corinna

doi:10.1038/1871117a0

Cited by 16 publications

(5 citation statements)

References 7 publications

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“…It has been shown that protein-starved animals incorporate labeled lysine in intestinal tissues at a higher rate than do normals, a finding that has been thought to indicate a re-direction of protein metabolism in favor of vital enzymes and structures in the intestinal organs (14). In our study the high uptake of labeled leucine into, and histologically normal appearance of small intestine is in agreement with these findings.…”

Section: Discussionsupporting

confidence: 82%

Studies of Protein Metabolism in Intestinal Epithelial Cells*

Lipkin¹,

Quastler²

1962

J. Clin. Invest.

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Section: Discussionsupporting

confidence: 82%

Studies of Protein Metabolism in Intestinal Epithelial Cells*

Lipkin¹,

Quastler²

1962

J. Clin. Invest.

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“…One group of investigators (17)(18)(19)(20) considered that this was an apparent phenomenon due to decrease in hepatic protein and shrinkage of amino acid pool in protein deficiency, whereas another group of workers (21--23) con cluded from their results that increased protein synthesis actually occurred in liver, even taking changes in pool size into consideration. In the present work on adult animals, results showed that 2-week protein depletion resulted in increas ed protein synthesis in the liver because both the specific and relative specific radio activities in the PFD group were generally higher than those in the Pair-fed and LA groups.…”

Section: Discussionmentioning

confidence: 99%

Effects of Protein and Energy Deficiency on the Incorporation of 14c-Chlorella Protein Hydrolysate Into Body Constituents of Adult Rats

Yamamoto

Wakabayashi

Niiyama

et al. 1974

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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The effects of protein and/or energy deficiency on 14C incorporation into body constituents and 14C output in expired air and urine were investi gated in adult rats using 14C-Chlorella protein hydrolysate. Rats were given a protein-free diet (PFD) for 2 weeks and control rats were fed ad libitum or pair-fed with the PFD group on a 12% lactalbumin diet (LA and Pair-fed, respectively). On the 15th day, animals received 14C Chlorella protein hydrolysate with 5g of their respective diet. One group of PFD animals was given tracer by stomach tube without food (PFD fast). Normal control rats ate about twice as much diet as the PFD group. The respiratory 14C output in the PFD group was identical with those in the LA and Pair-fed groups and was less than that in the PFD-fast group, The rate of protein synthesis, provisionally expressed as rela tive specific radioactivity, was more in the PFD group than in the normal group in the liver and less than the latter in the muscle. The LA group retained less total radioactivity in the body than the Pair-fed or PFD group, indicating high capability to hold the body protein in protein de ficiency. In addition, decreased conversion of amino acids to lipids and glycogen was observed in the PFD group. All these differences are interpreted as adaptations to protein shortage. On prolonged fasting (PFD-fast group), gluconeogenesis in the liver increased to provide energy, despite the protein deficiency. The relative importances of protein and energy for tissue protein synthesis are briefly discussed.It is well known that energy intake affects tissue protein synthesis and results in various changes in utilization of dietary protein (1-6). Although the intakes of

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“…After prolonged protein starvation parenterally administered radioactive amino acids are incorporated into the protein of the small intestinal mucosa to a greater extent than in any other organ (8,11,21). This ability of the small intestine to maintain its capacity for protein synthesis was confirmed.…”

Section: First Experimentsmentioning

confidence: 65%

“…In the earlier studies of the effect of protein depletion upon the incorporation of radioactive amino acids into intestinal mucosal protein, the amino acids were always given intraperitoneally (3,8,10,11,21) and it was found that there was more incorporation of the amino acid into small intestinal protein than in other tissues, and more than in the protein-fed animals. In the present study, oral administration of the amnino acid showed an even greater difference between protein-deprived and control animals.…”

Section: First Experimentsmentioning

confidence: 99%

“…Recent studies have shown that the jejunal mucosa is even more resistant than the ileal mucosa (4,5). The epithelium of the intestinal mucosa has a rapid turnover rate, which is reduced during protein deficiency (6) and starvation (7), but nevertheless this tissue synthesizes a large amount of protein each day (8,9). It is probably because of the rapid rate of growth that the small intestinal mucosa of the proteindeficient animal incorporates parenterally administered radioactive amino acids into protein more efficiently than other tissues (3,8,10,11).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Protein starvation and the small intestine

Hirschfield¹,

Kern²

1969

J. Clin. Invest.

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A B ST RA CT Weanling rats were fed diets which contained either no protein or 27% protein. In one experiment after 23-35 days both groups were given l-leucine-4,5-3H either intragastrically or intraperitoneally and then sacrificed 24 hr later. In a second experiment animals were given these diets for 21 days and sacrificed 3, 6, or 12 hr after either intragastric or intraperitoneal administration of the labeled leucine. In both experiments the intestinal mucosa of proximal and distal segments of the small intestine was scraped, weighed, the protein concentration measured, and the specific activty of the mucosal protein was determined.The wet weight of the mucosa and the protein concentration of the mucosa were significantly greater in the control animals than in the protein-depleted animals. The mucosal protein per 100 g of body weight was the same in the protein-deprived and the control groups. The specific activity of the intestinal mucosal protein was higer in the protein-deprived animals than in the control animals.In the protein-deprived animals the proximal segment incorporated more radioactive amino acid into mucosal protein than did the distal segment at 3, 6, 12, and 24 hr after the amino acid was given by mouth. A similar difference was found between the proximal and distal segments of the control animals 6 hr after oral adminisstration of l-leucine-'H. On the other hand, when the l-leucine-3H was given intraperitoneally to both groups

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Influence of Different Types of Malnutrition on the 14C-Lysine Metabolism in Young Rats

Cited by 16 publications

References 7 publications

Studies of Protein Metabolism in Intestinal Epithelial Cells*

Studies of Protein Metabolism in Intestinal Epithelial Cells*

Effects of Protein and Energy Deficiency on the Incorporation of 14c-Chlorella Protein Hydrolysate Into Body Constituents of Adult Rats

Protein starvation and the small intestine

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