Effect of Diet on Protein Synthesis and Nucleic Acid Levels in Rat Liver

Haider, Masood; Tarver, Harold

doi:10.1093/jn/99.4.433

Cited by 54 publications

(9 citation statements)

References 34 publications

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“…This was in line with previous results obtained in rats and dogs (14,42) and was also consistent with data in humans showing the lack of effect of diets supplying 9% or 24% of energy as protein, but containing identical levels of energy and fat, on albumin, fibrinogen, or fibronectin synthesis rates (6). These results also agree with the weak association demonstrated between albumin FSR and the level of dietary protein, when these ranged from the recommended daily allowance to an excess value of 25% (39).…”

Section: Discussionsupporting

confidence: 94%

“…This dose-dependent deceleration was observed in both the fasting and fed states, which was at variance with our previous findings when we observed a much more pronounced effect in the fed state (8). Moreover, the positive linear relationship that we described between the dietary protein level and both liver mass and liver protein content are totally in agreement with numerous other reports in rats (10,14,16).…”

Section: Discussionsupporting

confidence: 87%

“…This confirms our previous findings (8) that yielded a lower liver FSR (Ϫ34%) in rats adapted to an NP diet (with a high CHO content) than to an HP diet (with a low CHO content). Few other studies have produced conflicting results since the data available show either an absence of changes (12, 13), a slight decrease (10,14), or an increase (20) in liver protein synthesis when rats were switched from a normal to a high-protein diet. However, this last study was performed using a leucine flooding dose, which could impair the results due to the signal effect of this amino acid on protein synthesis.…”

Section: Discussionmentioning

confidence: 99%

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Dietary protein regulates hepatic constitutive protein anabolism in rats in a dose-dependent manner and independently of energy nutrient composition

Chevalier

Bos

Azzout‐Marniche

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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We had previously observed that drastic increases in protein consumption greatly modified hepatic protein anabolism in rats, but the confounding effects of other macronutrient changes or a moderate protein increase to generate the same modifications have not yet been established. This study examined the metabolic and hormonal responses of rats subjected to 14-day isoenergetic diets containing normal, intermediate, or high-protein levels (NP: 14% of energy, IP: 33%, HP: 50%) and different carbohydrate (CHO) to fat ratios within each protein level. Fasted or fed rats (n = 104) were killed after the injection of a flooding dose of (13)C-valine. The hepatic protein content increased in line with the dietary protein level (P < 0.05). The hepatic fractional synthesis rates (FSR) of protein were significantly influenced by both the protein level and the nutritional state (fasted vs. fed) (P < 0.0001) but not by the CHO level, reaching on average 110%/day, 92%/day, and 83%/day in rats fed the NP, IP, and HP diets, respectively. The FSR of plasma albumin and muscle did not differ between diets, while feeding tended to increase muscle FSR. Proteolysis, especially the proteasome-dependent system, was down-regulated in the fed state in the liver when protein content increased. Insulin decreased with the CHO level in the diet. Our results reveal that excess dietary protein lowers hepatic constitutive, but not exported, protein synthesis rates, independently of the other macronutrients, and related changes in insulin levels. This response was observed at the moderate levels of protein intake (33%) that are plausible in a context of human consumption.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

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Dietary protein regulates hepatic constitutive protein anabolism in rats in a dose-dependent manner and independently of energy nutrient composition

Chevalier

Bos

Azzout‐Marniche

et al. 2010

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Each value is lower than the estimated nutritional requirement for premature infants (36), although each is typical of the short-term nutritional support offered to infants recovering from hyaline membrane disease and receiving nourishment via a peripheral vein. Substantial evidence from both in vivo and in vitro studies suggests that malnutrition or undernutrition is associated with diminished albumin turnover, not the augmented FSR observed in this investigation (2)(3)(4)(5)(6)(7)(8). The available data suggest that the FSR could have been even greater if the infants had received more amino acids and total calories.…”

Section: Discussionmentioning

confidence: 57%

Albumin Synthesis in Premature Infants: Determination of Turnover with [15N]Glycine

et al. 1987

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Serum albumin concentrations in infants vary inversely with the degree of maturity, the blood albumin concentration of the premature newborn being lower than that of the baby born at term (I). It is unknown whether this phenomenon reflects reduced albumin synthesis or increased albumin turnover in less mature babies. A diminished synthetic rate appears to explain the hypoalbuminemia observed in malnourished rats (2-6) and children (7,8). However, such nutritional factors probably do not account for the relatively low albumin of babies whose growth is appropriate for gestational age. Immaturity of hepatic mechanisms subserving albumin synthesis might explain the low albumin. Conversely, the catabolism of albumin might be enhanced, especially in light of the observation that total body protein turnover is inversely related to the degree of maturity of premature infants (9).We have measured albumin turnover in a group of premature The results indicate that the relative hypoalbuminemia of premature infants is referable to an enhanced rate of albumin turnover rather than a diminution of albumin synthesis. Indeed, rates of albumin synthesis in these babies are much greater than those reported in the adult, with the albumin half-life in premature babies being less than half the adult value.

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“…These include changes in fluid and electrolyte balance [Brock, 1966;Kagan et al, 1972;Mann et al, 19751, cardiac structure and functions "utter et a1 , 1979;Piza et al, 1971;Smythe et al, 1962;Svoboda et al, 19661, nucleic acid synthesis [Haider and Tarver, 1969;Umana, 19651, plasma fibrinogen [Field and Dam, 19461, and placental morphology and functions [Mulay et al, 1980;Murthy et al, 1976;Van Marthens, 19771 We are not aware of any studies relating drug effects to these changes.…”

Section: Other Changesmentioning

confidence: 99%

Protein deficiency and drug interactions: A Review

Varma

1981

Drug Development Research

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Effect of Diet on Protein Synthesis and Nucleic Acid Levels in Rat Liver

Cited by 54 publications

References 34 publications

Dietary protein regulates hepatic constitutive protein anabolism in rats in a dose-dependent manner and independently of energy nutrient composition

Dietary protein regulates hepatic constitutive protein anabolism in rats in a dose-dependent manner and independently of energy nutrient composition

Albumin Synthesis in Premature Infants: Determination of Turnover with [15N]Glycine

Protein deficiency and drug interactions: A Review

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