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PubMed1990

Influence of dietary protein and recombinant porcine somatotropin administration in young pigs: growth, body composition and hormone status.

The influence of dietary protein and recombinant porcine somatotropin (rpST) administration on growth and body composition was investigated in barrows. Ten groups of six pigs starting at 30 kg were restrictively fed (approximately 80% of ad libitum) one of five diets containing 11, 15, 19, 23 or 27% protein. Diets contained skim milk (12%). Soybean meal diluted with cornstarch was used as the supplemental source of dietary protein. Diets were isocaloric (3.8 Mcal DE/kg) and all contained the same amount of lysine (18 to 20 g/kg). Thirty pigs were treated daily with rpST (100 micrograms/kg) by i.m. injection; the remaining pigs were treated with sterile diluent (control) for 42 d. Growth rate was greater in rpST-treated pigs at all levels of protein intake; however, the magnitude of the response to rpST treatment was lowest among pigs fed the diet containing 11% protein. Feed:gain ratio, backfat depth and carcass fat content were decreased in rpST-treated pigs compared to respective controls. Additionally, the concentration of carcass fat decreased concomitantly with an increase in dietary protein intake. Concentration of carcass protein increased linearly as dietary protein increased in control and rpST-treated pigs. In contrast, treatment with rpST was associated with an increased visceral mass; the concentration of protein and fat in the viscera was influenced by protein intake but not by rpST. These results, characterized by few treatment interactions, suggest that when energy intake is kept constant and appropriately fed pigs serve as controls, dietary protein and rpST influence growth and body composition by independent mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1993

Recombinant porcine somatotropin and dietary protein enhance protein synthesis in growing pigs.

The effects of a daily porcine somatotropin injection on protein synthesis rate in muscle (longissimus), liver and intestine, as influenced by dietary protein, were investigated in 17 pigs. The measurements were made at wk 3 of treatment following 1 wk for adaptation to the diet and 1 wk for determination of nitrogen balance. The fractional rates of protein synthesis in the muscle, liver and intestine were measured using a flooding dose of L-[1-13C]valine. Positive responses of weight gain and nitrogen balance were observed, primarily at higher dietary protein intake, after porcine somatotropin treatment. As expected, porcine somatotropin-treated pigs had a higher proportion of muscle and less fat. Fractional protein synthesis rate was 16% higher in the liver of porcine somatotropin-treated pigs (P < 0.05). In the longissimus muscle fractional protein synthesis rate increased with porcine somatotropin dose from 3.2 to 3.7%/d and from 4.1 to 5.1%/d at low and high protein intake, respectively (P < 0.05). The effect of dietary protein on fractional protein synthesis rate in longissimus was significant, but there was no porcine somatotropin x protein interaction. Ribonucleic acid concentration followed the same pattern as fractional protein synthesis rate in liver and longissimus. In the duodenal tissue, porcine somatotropin treatment depressed fractional protein synthesis rate (P < 0.05) without an effect of dietary protein and RNA concentration did not change. In porcine somatotropin compared with placebo-treated pigs, plasma glucose, insulin and insulin-like growth factor-I concentrations were elevated whereas plasma thyroxine was depressed and plasma triiodothyronine remained constant. There was no clear effect of dietary protein on plasma hormones. We concluded that, in pigs fed an adequate level of protein, porcine somatotropin stimulates protein synthesis in the liver and the muscle, primarily through increased ribosomal capacity.

Animals↗

PubMed1979

Effect of the combination of voluntary exercise and dietary protein levels on the deposition of glycogen, liver and serum lipids in mice.

The effects of voluntary exercise on the growth, glycogen of muscle and lipid contents of the liver and serum of mice fed different levels of dietary protein were investigated. In both the exercise and non-exercise groups, body weight gains were significantly greater in the 20% and 30% protein diet groups than in the 6% and 4% protein diet groups. After 6 weeks of age, it was shown that the amount of voluntary exercise by the 6% and 4% protein diet groups was greater than that by the 20% and 30% protein diet groups. As for hematological status, the raising of hemoglobin levels due to increasing dietary protein levels was further exaggerated by voluntary exercise. Hematocrit values rose with the increase in dietary protein levels. However the effect of exercise on hematocrit values was not clear. Liver glycogen levels, which were elevated with the increase in dietary protein levels, rose further due to exercise, though no changes were observed in muscle glycogen due to dietary protein levels and exercise. The lipid contents of the liver in all groups tended to be lower in exercise groups compared with non-exercise groups and it was observed that the high levels of dietary protein depressed the increase in liver lipids. Liver triglyceride levels of all groups fed the dietary protein levels except for the 20% casein diet group decreased due to voluntary exercise, and liver triglyceride levels were also lowered as dietary protein levels increased. The levels of serum triglyceride of all groups decreased due to voluntary exercise. This phenomenon was most remarkable in rats fed a 6% casein diet. The tendency for serum cholesterol levels to decrease due to exercise. However it was not further influenced by voluntary exercise in the 4% casein diet group.

Animals↗

PubMed2002

Epidemiological evidence of the association between dietary protein intake and blood pressure: a meta-analysis of published data.

The purpose of this study was to address the association between dietary protein intake and blood pressure (BP) by combining information from all epidemiological studies that presented quantitative estimates of dietary protein intake and BP assessment. A literature search of MEDLINE, restricted to human studies on dietary protein intake and BP, was conducted. References cited in related studies were also reviewed. The results were as follows. 1) Of eleven cross-sectional studies identified, nine were suitable for quantitative pooled analysis. In men (total sample, n=19,954 for SBP, and 19,982 for DBP), the pooled regression coefficients (betas) of SBP and DBP on dietary protein intake were -0.03 (0.001) and -0.025 (0.01) (both, p<0.01). In women (n=950), the pooled betas were -0.014 (0.01) for SBP (p<0.05) and -0.021 (0.00) for DBP (p<0.01). In the studies that reported data for both sexes (n=12,716 for SBP and 12,508 for DBP), the pooled betas were -0.029 (0.01) and -0.0156 (0.00) for SBP and DBP (both p<0.01). 2) Twenty-four-hour dietary recall and 24-h urine collection were the main methods used for diet assessment, and their pooled results were consistent with the combined results for both sexes. 3) Results from two longitudinal studies showed inverse associations between dietary protein intake and BP after 3 and 7 years' follow-up. In conclusion, a convincing cross-sectional inverse association between dietary protein intake and BP was demonstrated by the meta-analysis of nine population-based studies. The evidence from longitudinal epidemiological studies was limited. Further studies will be needed to confirm the hypothesis of the inverse dietary protein-BP association.

Blood Pressure↗

PubMed1988

Importance of early initiation of dietary protein restriction for the prevention of experimental progressive renal disease.

The effect of dietary protein restriction on the progress of renal dysfunction was investigated in rats with adriamycin (ADR)-induced progressive glomerular disease. Dietary protein was reduced from 20% (normal diet) to 5% (low protein) immediately after (ADR-0w), 8 weeks (ADR-8w) or 16 weeks (ADR-16w) after the repeated injection of ADR. In the unrestricted (ADR-UR) group rats were fed 20% of protein throughout the 24-week experiment. Massive urinary protein developed immediately after ADR injection and significantly decreased by reducing dietary protein in all the groups (ADR-0w, ADR-8w, ADR-16w). However, plasma protein and serum albumin were low irrespective of the improvement of urinary protein. BUN and serum creatinine were unchanged in ADR-0w and ADR-8w groups, while they were increased in ADR-16w and ADR-UR groups. Glomerular sclerosis and tubular atrophy were much less severe in ADR-0w and ADR-8w than in ADR-16w and ADR-UR groups. The results indicate that dietary protein restriction checks the further progress of renal dysfunction. The importance of the time when protein intake should be reduced is discussed.

Animals↗

PubMed2004

Dietary protein and the risk of cholecystectomy in a cohort of US women: the Nurses' Health Study.

In animals, vegetable protein can inhibit gallstone formation. Epidemiologic studies of dietary protein in relation to gallstone disease are sparse, and the effects of dietary protein of different origins are not clear. The authors aimed to examine the relation between dietary protein intake and risk of cholecystectomy among participants in the Nurses' Health Study, a cohort study of US women in 11 states. During 20 years of follow-up (1980-2000), the authors documented 7,831 cases of cholecystectomy. After adjustment for age, other known or suspected risk factors, and specific fats in a multivariate model, the relative risk of cholecystectomy for women in the highest quintile of dietary total protein intake compared with women in the lowest quintile was 1.00 (95% confidence interval (CI): 0.93, 1.08; p for trend = 0.46). When extreme quintiles were compared, the relative risk for animal protein intake was 1.07 (95% CI: 0.98, 1.15; p for trend = 0.08), whereas the relative risk for vegetable protein intake was 0.79 (95% CI: 0.71, 0.88; p for trend < 0.0001), with a significant dose-response relation. Additional mutual adjustment between animal and vegetable proteins did not materially alter the risks. These results suggest that increased consumption of vegetable protein in the context of an energy-balanced diet can reduce the risk of cholecystectomy in women.

Adult↗

PubMed1982

Studies on the effect of dietary protein and fat content upon DDT metabolism in rat liver.

Rats were supplied with 25 kinds of food, which were divided into 5 classes of protein and 5 classes of fat content, to examine the effect of dietary protein and fat on the metabolism and retention of DDT in the liver. The results suggested that dietary protein and fat changed DDT and its metabolites concentration in liver. The concentration of DDT decreases according to the increase of dietary protein content. The concentration of DDT and its metabolites in liver increases when the dietary fat content increases. Polynomial and multiple regression analyses were carried out to confirm the effect of dietary protein and fat on DDT metabolism. The results suggest that the residual concentration of DDT and its metabolites (DDD and DDE) is a function of dietary protein and fat content, and can be represented in equation form. The estimation of the concentration of DDT and its metabolites from the equation agrees well with the measured concentration in liver.

Animals↗

PubMed2003

Dietary protein and bone health.

The effects of dietary protein on bone health are paradoxical and need to be considered in context of the age, health status and usual diet of the population. Over the last 80 years numerous studies have demonstrated that a high protein intake increases urinary Ca excretion and that on average 1 mg Ca is lost in urine for every 1 g rise in dietary protein. This relationship is primarily attributable to metabolism of S amino acids present in animal and some vegetable proteins, resulting in a greater acid load and buffering response by the skeleton. However, many of these early studies that demonstrated the calciuric effects of protein were limited by low subject numbers, methodological errors and the use of high doses of purified forms of protein. Furthermore, the cross-cultural and population studies that showed a positive association between animal-protein intake and hip fracture risk did not consider other lifestyle or dietary factors that may protect or increase the risk of fracture. The effects of protein on bone appear to be biphasic and may also depend on intake of Ca- and alkali-rich foods, such as fruit and vegetables. At low protein intakes insulin-like growth factor production is reduced, which in turn has a negative effect on Ca and phosphate metabolism, bone formation and muscle cell synthesis. Although growth and skeletal development is impaired at very low protein intakes, it is not known whether variations in protein quality affect the achievement of optimal peak bone mass in adolescents and young adults. Prospective studies in the elderly in the USA have shown that the greatest bone losses occur in elderly men and women with an average protein intake of 16-50 g/d. Although a low protein intake may be indicative of a generally poorer diet and state of health, there is a need to evaluate whether there is a lower threshold for protein intake in the elderly in Europe that may result in increased bone loss and risk of osteoporotic fracture.

Bone and Bones↗

PubMed1991

Changes in cerebrospinal fluid and plasma amino acid concentrations with elevated dietary protein concentration in dogs with portacaval shunts.

Effects of dietary protein concentration on plasma and cerebrospinal fluid (CSF) amino acids (AA) in dogs with portacaval shunts (PCS) were examined. An 18% protein purified diet (18P) was fed to 4 PCS dogs and 2 controls; at week 10, 2 of the PCS dogs were switched to 36% protein (36P) until week 28. Effects of the diet switch on plasma and CSF AA in 8 normal dogs were determined in another experiment. Neither surgery nor protein level significantly affected average food intake (weeks 10-28). Plasma amino acid patterns typical of PCS animals were observed: phenylalanine and tyrosine increased and branched chain AA decreased with shunting (p less than 0.05). Plasma phenylalanine increased further with 36P in PCS dogs (p less than 0.05), but was not affected by dietary protein concentration in controls. With 36P: CSF arginine, serine, histidine, tryptophan, phenylalanine, glutamate and glutamine increased in PCS dogs; but only arginine decreased in CSF of controls (p less than 0.05). In PCS dogs, significant CSF AA changes with elevated dietary protein were unrelated to plasma AA changes.

Amino Acids↗

PubMed1982

Effect of dietary protein and energy on broiler performance and production costs.

Varying levels of dietary protein (16, 20, 24, 28, 32, 36%) and energy (2600, 2800, 3000, 3200, 3400, 3600 kcal [metabolizable energy] ME/kg) were fed in a factorial arrangement to broilers to determine the effect of alteration in nutrient density on performance and economic traits. Body weight and feed efficiency improved with increased dietary protein or energy. However, a significant interaction between protein and energy indicated the importance of a balanced energy: protein ratio to achieve optimum performance. Sex differences in protein requirements were observed for 49-day body weights. Returns over feed costs remained essentially constant, providing a balance between dietary protein and energy was maintained. However, an increase above 28% crude protein or 3400 kcal ME/kg resulted in reduced returns as did excessive quantities of one nutrient relative to the other. Male broilers were able to accommodate a higher level of dietary protein (24%) than female broilers (20%) before returns were reduced. Regression equations were derived for prediction of performance and economic parameters. Reliable estimates were obtained with the inclusion of protein or energy intake in addition to diet composition.

Animal Feed↗

PubMed2002

Effects of dietary protein and fermentable fiber on nitrogen excretion patterns and plasma urea in grower pigs.

Effects of dietary protein concentration (high, 18.5; low, 15.7%) and fermentable fiber (control; soyhulls, SH; and sugar beet pulp, SBP) on N excretion patterns and plasma urea were tested in a 2 x 3 factorial arrangement. The objectives were: 1) to determine if reduced dietary protein together with fermentable fiber would reduce urinary N excretion further than a single diet manipulation, 2) to determine if effects of diet manipulations were similar between pigs with restricted and free access of feed, and 3) to further develop predictions of urinary N excretion using plasma urea. Diets were formulated to 3.30 Mcal digestible energy (DE)/kg and 2.4 g of digestible lysine per Mcal DE, and supplemented with lysine, methionine, tryptophan, threonine, isoleucine, leucine, or valine to ensure meeting an ideal AA profile. Pigs (30.5 +/- 3 kg; n = 36) were housed in metabolism crates with restricted access to feed (3 x 110 kcal DE/kg BW(0.75)) from d 1 to 18, and free access from d 19 to 26. Feces and urine were collected from d 15 to 18 and d 23 to 26, and blood was sampled on d 17 and 25. With restricted access to feed, urinary N was reduced 28% and N retention was reduced 12% for the low- compared to high-protein diet (P < 0.01; as g/d). Fecal N was increased 4% units for SH and 6.5% units for SBP (P < 0.01; as % of N intake) and urinary N was reduced 5% units for SH (P < 0.10) and 9% units for SBP (P < 0.05) compared to the control. With free access to feed, urinary N was reduced 27% (P < 0.05; as g/d) and N retention was reduced 7% (P < 0.10) for the low- compared to high-protein diet. Fecal N was increased 5% units for SH and 9% units for SBP (P < 0.001; as % of N intake), and urinary N was reduced 9% units for SH and 10% units for SBP (P < 0.01) compared to the control. For either restricted or free access to feed, fermentable fiber did not affect N retention (P > 0.10). A protein x fiber interaction was not observed for urinary N excretion (P > 0.10), indicating that reducing dietary protein and including fermentable fiber reduced urinary N excretion in an additive manner. Daily urinary N excretion was related positively and linearly with plasma urea in pigs with free access to feed (R2 = 0.71; at 0800). In summary, reduction of dietary protein reduced urine N excretion, and fermentable fiber shifted N excretion from urine to feces. Effects of dietary protein and fermentable fiber on reducing urinary N excretion are additive.

Animals↗

PubMed2005

Molecular cloning of chicken hepatic histidase and the regulation of histidase mRNA expression by dietary protein.

Chicken hepatic histidase activity varies with dietary protein consumption, but the mechanisms responsible for this alteration in activity are unclear. In the present research, the complete coding sequence and deduced amino acid sequence for chicken histidase was determined from clones isolated from a chicken liver cDNA library. The deduced amino acid sequence of chicken histidase has greater than 85% identity with the amino acid sequences of rat, mouse, and human histidase. In a series of four experiments, broiler chicks were allowed free access for 1.5, 3, 6, or 24 h to a low (13 g/100 g diet), basal (22 g/100 g diet) and high (40 g/100 g diet) protein diet. In the final experiment 5, chicks were allowed free access for 24 h to the basal, high protein diet or the basal diet supplemented with three different levels of l-histidine (0.22 g/100 g diet, 0.43 g/100 g diet or 0.86 g/100 g diet). There were no differences in the expression of the mRNA for histidase at 1.5 h, but at 3 h, histidase mRNA expression was significantly (P < .05) greater in chicks fed the high protein diet compared to chicks fed the low protein diet. At 6 and 24 h, histidase mRNA expression was significantly enhanced in chicks fed the high protein diet, and significantly reduced in chicks fed the low protein diet, compared with chicks fed the basal diet. Histidase mRNA expression was not altered by supplementing the basal diet with histidine. The results suggest that previously observed alterations in the activity of histidase, which were correlated to dietary protein intake, are mediated by rapid changes in the mRNA expression of this enzyme, and are not necessarily related to dietary histidine intake.

Amino Acid Sequence↗

PubMed1998

Dietary protein and energy requirements in ESRD patients.

The published reports of dietary protein and energy intake and protein and energy requirements for maintenance hemodialysis (MHD) patients and chronic peritoneal dialysis (CPD) patients are reviewed. Evidence indicates that the dietary energy intake of patients undergoing MHD or continuous ambulatory peritoneal dialysis (CAPD) is less than normal. Dietary protein intake in various surveys averages approximately 1.0 g/kg/d. The energy expenditure of MHD patients appears to be normal or slightly increased during resting and normal during various other daily activities. Energy expenditure in CAPD patients appears normal. Nitrogen balance and anthropometric studies in MHD or CAPD patients ingesting controlled diets in a metabolic unit research ward also indicate that dietary energy requirements are normal and are approximately 35 to 38 kcal/kg/d in MHD patients. For CAPD patients, total energy requirements (from diet and dialysate) also appear to be 35 to 38 kcal/kg/d. These recommended energy intakes are for adult patients aged approximately 60 years or younger. Thus, the low dietary energy intakes of MHD and CPD patients are maladaptive. Nitrogen balance studies indicate that a safe dietary allowance for protein is approximately 1.2 g/kg/d for MHD patients and 1.2 to 1.3 g/kg/d for CAPD patients. Because the nutritional status of patients at the onset of chronic dialysis therapy is a strong predictor of both their nutritional status during the course of chronic dialysis treatment and their subsequent morbidity and mortality, it is important to maintain good nutritional status in patients with chronic renal failure before their development of end-stage renal disease (ESRD) and establishment on chronic dialysis. Evidence indicates that there is a reduction in dietary protein and energy intake and a gradual deterioration of nutritional status in patients with chronic renal insufficiency as the glomerular filtration rate (GFR) decreases progressively to less than 50 to 60 mL/min/1.73 m2. More studies are needed to assess dietary protein and energy requirements both for MHD and CPD patients who are clinically stable and for those who have sustained comorbid conditions that increase energy expenditure or protein nitrogen appearance.

Dietary Proteins↗

PubMed1990

The effects of age and dietary protein restriction on the pharmacokinetics of theophylline in the rat.

The influence of dietary protein levels on theophylline kinetics was examined in male Fischer 344 virgin rats of 2, 14 and 20 months of age fed for four weeks on a 23% (control) or 5% (low) protein diet ad libitum. Protein deficiency led to a significant decrease in body weight gain for the 2 month old rats (10.9% versus 26.5%). In addition, decreases in total body weight of 7.5% and 15.3% were seen for the 14 and 20 month old rats, respectively, on a low protein diet. Total proteins and albumin levels in plasma were not significantly affected by age or dietary protein levels. After intravenous administration of 10 mg/kg aminophylline, the average mean residence time (MRT) was significantly longer in 20 month old rats as compared to the younger rats, while 14 month old rats had a greater elimination rate constant than the 2 and 20 month old rats. There were significant reductions in the mean steady-state apparent volume of distribution (Vss) in the 2 and 14 month old rats on a low protein diet of 31% and 18%, respectively, while there was no difference between the diets in 20 month old rats. In addition, the Vss decreased from 0.71 L/kg to 0.57 L/kg in the 2 and 20 month old rats, respectively, on a normal protein diet. Dietary protein deficiency led to a significant reduction of total body clearance from approximately 73 to 45 ml/hr/kg in the 2 and 14 month old rats.2+p

Aging↗

PubMed1993

Dietary protein and cholesterol metabolism in small intestines.

Effect of quality and quantity of dietary protein on blood cholesterol and cholesterol metabolism in small intestines of rat was examined. Compared to casein, bengalgram in the diet decreased blood and intestinal cholesterol. It is suggested that this effect may be due to low levels of leucine in bengalgram protein and less release of insulin, an activator of HMG CoA Reductase. Low casein in the diet (12%) caused a decrease of blood and intestinal cholesterol while high casein in the diet (24%) caused a decrease of intestinal cholesterol only. It is suggested that both qualitywise and quantitywise, dietary protein influences body cholesterol. It is known that the nature and the quality of dietary fat and carbohydrates directly influence the metabolism of cholesterol. The dietary proteins might also have a significant role. Proteins are needed for the synthesis of enzymes required for the anabolism and catabolism of cholesterol and a few protein-aminoacids like leucine have a direct influence on cholesterol metabolism. Bengalgram was chosen for studying the effect of the quality of protein on cholesterol metabolism as there are reports in the literature that bengalgram feeding reduces blood cholesterol. Different amounts of casein-containing diet were used in a separate set of experiments to investigate the effects of low and high protein diets on cholesterol metabolism i.e. quantitative effects of dietary protein. For many years, liver was enjoying the privilege of maintaining the homeostasis of blood cholesterol. Recently it has been shown that small intestines also synthesises considerable amounts of cholesterol. Hence, cholesterol metabolism was investigated separately in duodenum, jejunum and ileum.

Animals↗

PubMed1996

Precursor pool for hepatic protein synthesis in humans: effects of tracer route infusion and dietary proteins.

The estimation of the hepatic protein synthesis precursor pool was investigated through the measurement of very low-density lipoprotein (VLDL) apolipoprotein (apo)B100 labeling in healthy volunteers. L-[1-13C]leucine and L-[5,5,5-2H3]leucine were administered intravenously and intragastrically, respectively. Subjects were continuously fed with isoenergetic meals providing either 16% protein or no protein. The labeling of leucine incorporated into VLDL apoB100 (leucine-apoB) was lower than plasma leucine or alpha-ketoisocaproate (KIC) enrichments with the intravenous tracer. By contrast, with the oral tracer, leucine-apoB enrichment was higher than either plasma free leucine or KIC labeling. The KIC and leucine-apoB enrichments relative to plasma leucine enrichment were not affected by protein intake. Albumin or fibrinogen synthesis rates were similar whatever the administration route of the tracer when leucine-apoB was used to indicate the precursor, which was not the case for plasma leucine or KIC. The present data suggest that leucine-apoB enrichment represents a reliable indicator of the hepatic precursor pool for protein synthesis. The effect of dietary protein on the calculated rates of albumin and fibrinogen synthesis is also reported in relation to the choice of the precursor.

Adult↗

PubMed1995

Dietary protein levels affect water intake and urinary excretion of magnesium and phosphorus in laboratory cats.

The effects of dietary protein levels on food and water intake, and urinary excretion of magnesium (Mg) and phosphorus (P) were examined in cats fed dry-type diets. Four adult female cats were used for trials in a 4 x 4 Latin square design, and fed diets with increasing protein content (25.9, 38.3, 51.4 or 65.2% in dry matter) daily from 9:00 to 13:00. While daily food intake was almost constant regardless of the dietary protein level, water intake and urine volume increased with increasing the dietary protein. Daily urinary excretion of P increased in response to the increase in dietary protein level. The urinary concentration of P was positively related to nitrogen (N)-intake. In contrast, daily urinary excretion of Mg was not affected by the dietary protein level, and the urinary concentration of Mg was negatively related to N intake. A dry-type diet with a high protein content might be effective in preventing the deposition of Mg salts in the urinary tract of cats under the meal-fed condition without affecting food intake because of both the lower concentration of urinary Mg resulting from the increase in urine volume and, probably, urinary acidification.

Animals↗

PubMed1983

Effects of dietary protein on the pharmacokinetics of butylated hydroxytoluene (BHT) in rats.

The effects of dietary protein on the metabolism of butylated hydroxytoluene (BHT) were examined in the present study by comparison of the pharmacokinetics of BHT in rats fed different levels of dietary protein. Groups of young female rats were fed diets containing 24%, 8%, or 4% protein, as supplied from casein, for 4 weeks. At the end of the feeding period, a single oral dose of 500 mg BHT/kg was administered intragastrically to each rat. The serum BHT concentration was then measured at intervals during the first 12 hr following BHT administration. Several kinetic measurements were obtained from both the zero-order and first-order plots of serum BHT concentration versus time. Reduced BHT metabolism as indicated by increased concentration and delayed clearance of BHT in the circulation was found among rats fed 4% dietary protein compared to those fed 24% protein. On the other hand, no significant alteration was observed in any of the kinetic parameters obtained from rats fed 8% dietary protein. It was concluded that metabolism of BHT is reduced only when protein consumption is reduced to a 4% dietary level.

Animals↗