Mineral status in selenium-deficient rats compared to selenium-sufficient rats fed vitamin-free casein-based or torula yeast-based diet

To clarify the mineral status in selenium (Se)-deficient rats fed a vitamin-free casein (VFC)-based or torula yeast (TY)-based diet, 24 weanling male Wistar rats were divided into 4 groups fed diets using VFC or TY as the protein source and containing Se at sufficient (0.5 μg/g,⁺Se) or deficient (0.019 μg/g for VFC-based and <0.005 μg/g for TY-based diets,⁻Se) level for 8 wk. TY supplied a larger amount of extra minerals (Na, K, Ca, Mg, Fe, Mn, Zn, and Cu) except Se than VFC. Se concentration and glutathione peroxidase activity were significantly lower in TY-fed rats than in VFC-fed rats, as well as in⁻Se rats compared to⁺Se rats. Compared to⁺Se rats, Fe concentration was higher in liver and muscle of⁻Se rats fed the VFC-based diet and in plasma, heart, liver, and tibia of⁻Se rats fed the TY-based diet. Compared to⁺Se rats, decreases of Mn concentration appeared in plasma, heart, and tibia of VFC-fed⁻Se rats and in brain, heart, liver and tibia of TY-fed⁻Se rats. There was also a little imbalance in Ca, Mg, Na, K, and Cu caused by Se deficiency. The results indicated that Se deficiency induced the mineral imbalance in rats, especially an increase in Fe and decrease in Mn, which was more severe in TY-fed rats than VFC-fed rats. However, TY cannot be used as a model for both Se and other mineral deficiency because of the extra minerals except Se found in TY. Instead, VFC can be employed, which contains fewer minerals except Se than TY and also can produce a severe degree of Se deficiency.     

Effects of selenium and tellurium on the activity of selenoenzymes glutathione peroxidase and Type I iodothyronine deiodinase, trace element thyroid level, and thyroid hormone status in rats

Tellurium (Te) and selenium (Se) belong chemically to the VIa group of elements. Se represents an essential element closely related to thyroid function. Te has growing application in industrial processes. Little is known about the Te biological activity, particularly with respect to potential chemical interactions with Se-containing components in the organism. In this study, female Wistar rats (body weight: 115-120 g) received sodium selenite pentahydrate (10 mg/L) or sodium tellurite (9.4 mg/L) in drinking water for 6 wk. Additional groups of rats received their combination with zinc sulfate heptahydrate (515 mg/L). The stimulation of 5’-DI-I activity due to selenite (to 158%, p<0.01) or tellurite treatment (to 197%, p<0.01) was seen; however, no effect on glutathione peroxidase was demonstrated in this experiment. An elevation of T4, T3, and rT3 serum levels was measured in the Se+Te-treated group; T4 and rT3 levels were elevated in the Te+Zn-treated group. Te accumulates in the thyroid gland and influences the zinc thyroid level. Te treatment alone and in combination with Se or Zn decreased the iodine thyroid concentration to 65-70% of the control value. Further studies are needed to clarify the nature and effects of these events.     

The effect of barium selenate injection on selenium concentration and glutathione peroxidase activity in blood of pregnant ewes fed selenium-deficient diet

Selenium (Se) levels in whole blood and plasma, and glutathione peroxidase (GSH-Px) activities in red cells and plasma were measured in ewes fed an Se-deficient diet injected with barium selenate before breeding season. Highly significant increases in Se levels and GSH-Px activities (P<0.001) were observed throughout the gestation period and during lactation. In the control group, Se levels and GSH-Px activities decreased significantly (P<0.001), and were at critically low levels during lambing and lactation periods.     

Effect of iodine supplement on iodine status and 5′-deiodinase activity in the brain of neonatal rats with iodine deficiency

The weanling Wistar rats of iodine deficiency were divided into three groups for supplementation of different levels of iodine (iodine-excessive [IE], iodine-adequate [IA], and iodine-deficient [ID]), with a control group (C). The iodine content in the thyroid was determined by epithermal neutron activation analysis. The activities of 5′-deiodinase and 5-deiodinase in the brains were assayed by determining the conversion ratios of T4 to T3 and rT3, respectively. The thyroid hormones levels in serum were also tested. The results indicated that the ID group had a goiter containing a small amount of iodine, but the IE group had a slightly swollen thyroid with rich iodine; the concentration of iodine per unit mass of thyroid was lower in group IE than in groups IA and C. The highest 5′-deiodinase and lowest 5-deiodinase activities in group ID and the lowest 5′-deiodinase activity in group IE were found. The iodine deficiency or excess resulted in a compensated hypothyroid state. The results suggest that the iodine status and the deiodinases activities would become normal for the rats of iodine deficiency if adequate iodine is supplemented soon after birth. Meanwhile, it is also critical to avoid excessive intake of iodine to reduce the risk for overcorrecting.     

Adaptive changes in total pyruvate dehydrogenase activity in lipogenic tissues of rats fed high-sucrose or high-fat diets

• 1.1. Pyruvate dehydrogenase complex (PDC) activity was measured in several tissues of rats fed for 7 or 15 days on control, or high-sucrose or high-fat diets.
• 2.2. Total activity in adipose tissue increased in the three groups 3–4-fold as compared with chow-fed animals in the first week. Total activity was 60% lower in rats fed the diet containing 22% corn oil for 2 weeks.
• 3.3. Hepatic total and PDCa activities were 50–80% higher in rats fed the sucrose diet for 7 or 15 days and decreased 30–40% in those fed on the high-fat diet for 2 weeks.

     

Zinc supplementation on serum levels and hepatic conversion of thyroid hormones in obese (ob/ob) mice

The supplemental effects of zinc on thyroid status in obese (ob/ob) mice were studied. Four-week-old obese mice and their lean controls were fed either a basal diet or a zinc-supplemented diet (200 mg/kg diet) for 8 wk. Following the 8-wk basal diet, obese mice had lower serum T4 values, as well as hepatic T4 and T3 values, than lean mice (p < 0.05). A significant decrease in hepatic 5′-deiodinase activity was also observed in obese mice. Dietary zinc supplementation significantly reduced serum T4 levels in both the obese and lean mice. However, the zinc-supplemented effects on diminishing hepatic T4 and T3 values, as well as on 5′-deiodinase activities, were found only in obese mice (p < 0.05). Furthermore, the 5′-deiodinase activities in hepatic microsomal pellets after incubation with various zinc concentrations (0.5, 1.0, and 2.5 mM) were also examined. The 5′-deiodinase activities, in hepatic samples from all mice, were significantly attenuated by zinc treatments. However, this effect was more predominant in obese mice following the addition of 0.5 mM zinc. This study suggests that a lower hepatic 5′-deiodinase activity, resulting from a higher zinc level, might be related to abnormal energy metabolism in theob/ob mice.     

Tissue manganese levels and liver pyruvate carboxylase activity in magnesium-deficient rats

To investigate the manganese status in magnesium deficiency, 40 male Wistar rats, 3 wk old, were divided into two groups and fed a magnesium deficient diet or a normal synthetic diet for 2 wk. Dietary magnesium depletion decreased magnesium levels in brain, spinal cord, lung, spleen, kidney, testis, bone, blood, and plasma, while it elevated the magnesium level in liver. In magnesium-depleted rats, calcium concentration was increased in lung, liver, spleen, kidney, and testis, while it was decreased in tibia. In magnesium-depleted rats, manganese concentration was decreased in plasma and all tissues except adrenal glands and blood. Dietary magnesium depletion diminished pyruvate carboxylase (EC 6.4.1.1) activity in the crude mitochondrial fraction of liver. Positive correlation was found between the liver manganese concentration and the pyruvate carboxylase activity. In the magnesium-depleted rats, glucose was decreased while plasma lipids (triglycerides, phospholipids, and total cholesterol) were increased. These results suggest that dietary magnesium deficiency changes manganese metabolism in rats.     

Effects of high salt diets and taurine on the development of hypertension in the stroke-prone spontaneously hypertensive rat

Summary. Taurine is present in high concentrations in mammalian tissues and has been implicated in cardiovascular control mechanisms. The aim of the present study was to evaluate the ability of taurine to attenuate salt-induced elevations in blood pressure and markers of damage to the kidney and cardiovascular system in stroke prone spontaneously hypertensive rats (SPSHR). Male SPSHR (6 weeks old) were placed on high salt diets that contained 1% (w/w) NaCl added to their normal chow for 84 days and then were switched to 3% added NaCl for the remaining 63 days of the study. SPSHR was given 1.5% taurine in the drinking water (n = 8), a taurine free diet (n = 8) or normal chow (n = 8). A final control group (n = 6) was not given high salt diets. High salt diets caused an acceleration in the development of hypertension in all groups. Taurine supplementation reduced ventricular hypertrophy and decreased urinary excretion of protein and creatinine. The taurine free diet did not alter serum or urinary excretion of taurine, but did result in elevated urinary nitrogen excretion, increased serum cholesterol levels, and impaired performance in a spatial learning task. Alterations in dietary taurine intake did not alter urinary or serum electrolytes (Na⁺, K⁺), but taurine supplementation did attenuate a rise in serum calcium seen with the high salt diets. Urinary excretion (μg/24 h) of epinephrine and dopamine was significantly reduced in SPSHR given 1% NaCl in the diet, but this effect was not seen in SPSHR on taurine free or supplemented diets. Taurine supplementation showed cardioprotective and renoprotective effects in SPSHR given high salt diets. Received April 12, 1999/Accepted September 13, 1999     

Indispensable amino acid concentrations decrease in tissues of stomachless fish,common carp in response to free amino acid- or peptide-based diets

Summary. The premise that free amino acid or dipeptide based diets will resolve the nutritional inadequacy of formulated feeds for larval and juvenile fish and improve utilization of nitrogen in comparison to protein-based diets was tested in stomachless fish, common carp (Cyprinus carpio L.) larvae. We examined the postprandial whole body free amino acid (FAA) pool in fish that were offered a FAA mixture based diet for the duration of 2 or 4 weeks. We found that the total amount and all indispensable amino acids concentrations in the whole body decreased after a meal. We then fed juvenile carp with dietary amino acids provided in the FAA, dipeptide (PP), or protein (live feed organisms; brine shrimp Artemia salina nauplii, AS) forms. Histidine concentrations in the whole fish body increased in all dietary groups after feeding whereas all other indispensable amino acids decreased in FAA and PP groups in comparison to the AS group. Taurine appears to be the major osmotic pressure balancing free amino acid in larval freshwater fish which may indicate a conditional requirement. We present the first evidence in larval fish that in response to synthetic FAA and PP diets, the whole body indispensable free AA concentrations decreased after feeding. This study shows that amino acids given entirely as FAA or PP cannot sustain stomachless larval fish growth, and may result in depletion of body indispensable AA and most of dispensable AA. The understanding of these responses will determine necessary changes in diet formulations that prevent accelerated excretion of amino acids without protein synthesis.     

Daily zinc supplementation effect on zinc deficiency in rats during prolonged restriction of motor activity

The objective of this investigation was to evaluate the effect of 47 mg zinc supplementation on deficiency of zinc in rats during 98 d of restriction of motor activity (hypokinesia), which appeared by higher plasma zinc concentration. One Hundred 13-week-old Sprague-Dawley male rats weighing 360–390 g were used to perform the studies: They were equally divided into four groups: 1. Unsupplemented control animals (UCA); 2. Unsupplemented hypokinetic animals (UHA); 3. Supplemented control animals (SCA); and 4. Supplemented hypokinetic animals (SHA). For the simulation of the effect of hypokinesia (HK), the UHA and SHA were kept in small individual cages made of wood, which restricted their movements in all directions without hindering food and water intake. The SCA and SHA received daily with their food an additional amount of zinc. Before and during the experimental period of 98 d, plasma, urinary and fecal zinc, balance of zinc, food intake, and body weight were determined at different intervals. In the SHA and UHA, the concentration of zinc in plasma, and the elimination of zinc in urine and feces increased significantly when compared with the SCA and UCA, whereas the balance of zinc was negative. The body weight and food intake decreased significantly in the SHA and UHA when compared with the SCA and UCA. The increased plasma concentration of zinc in both the SHA and UHA groups was in contrast to the observed hypozincnemia during prolonged immobilization as during prolonged hospitalization. This reaction suggests that there may be some other mechanisms that are affecting the process of control and regulation of zinc metabolism during prolonged HK. It was concluded that exposure to prolonged restriction of motor activity of rats induces significant increases in plasma concentration, fecal and urinary elimination of zinc in the presence of negative zinc balance and regardless the daily intake of large amounts of zinc with their food, leading to zinc deficiency.     

Sexual differences in 5′-deiodinase activity in the harderian gland of Syrian hamsters and the effect of pinealectomy: Regulation by androgens

Sexual differences on thyroxine 5′-deiodinase (5′-D) in the Harderian gland of Syrian hamsters were investigated. We compared the 24-h profile of 5′-D activity in male and female hamsters, observing a clear rhythm in males but not in females. Female values were always significantly higher than male ones. After pinealectomy day/night variations in male 5′-D activity at the time points studies were abolished, results that are in correlation with serum thyroid hormones. We also studied the regulation by androgen of the enzyme activity. Basal 5′-D activity increased in castrated males and levels fell when animals were implanted with testosterone or its product 5α-dihydrotestosterone (DHT). Female 5′-D activity was also inhibited by androgens. As only the addition of DHT in the presence of epitestosterone, an inhibitor of the conversion of testosterone on DHT, in castrated males was able to decrease 5′-D activity to control animal levels, we suggest a probable direct effect of DHT by itself. © 1996 Wiley-Liss, Inc.     

A comparative study of 5’nucleotidase and alkaline phosphatase in human placenta during development

Activities and a few properties of alkaline phosphatase and 5’-nucleotidase were compared in the developing human placenta. Both the enzymes were mostly membrane-bound and displayed similar developmental patterns with the highest activities at 24/26 weeks of the placenta. L-Phenylalanine, L-tryptophan and L-leucine were inhibitors of alkaline phosphatase, whereas they had no effect on the 5’-nucleotidase. Alkaline phosphatase from a late stage of gestation appeared to be almost heat-stable. An appreciable part of 5’-nucleotidase was also resistant to heat inactivation and this fraction varied with gestational age of the tissue. For both the enzymes, V_max changed without alteringK _m values with periods of gestation. Ca²⁺, Mg²⁺ and Mn²⁺ ions stimulated the alkaline phosphatase activity and Hg²⁺, Zn²⁺, Cu²⁺, Ni²⁺ were inhibitory. 5’-Nucleotidase was not activated by any of these cations. EDTA and Concanavalin A inhibited both the enzymes, although the extent of inhibition was different and also varied with gestation.     

Comparison of selenium level and glutathione peroxidase activity in tissues of vitamin B6-deficient rats fed sodium selenite or DL-selenomethionine

The effect of vitamin B₆ on the levels of tissue selenium (Se) and glutathione peroxidase (GSH-Px) was studied. Male Wistar 4-week-old rats were fed a vitamin B₆-Se-deficient basal diet for 2 weeks, then divided into 10 groups of five or six rats and fed their respective diets for 4 weeks. The experimental design was a 2×2×2 factorial with two levels of vitamin B₆, two forms of Se, and two levels of Se, plus two extra groups (vitamin B₆-supplemented and deficient without Se). Vitamin B₆ was 0 and 250 μg pyridoxine-HCl/100 g of diet; Se forms were Na₂SeO₃ and DL-selenomethionine; Se levels were 0.5 and 5.0 mg Se/kg of diet. Regardless of form or level of Se, vitamin B₆-deficient rats had lower body weights and organ weights than vitamin B₆-supplemented rats. At 5.0 mg Se/kg of diet, Na₂SeO₃ caused a further depression. Vitamin B₆ deficiency resulted in a higher Se level and GSH-Px activity in plasma of rats fed selenomethionine. However, Se content an GSH-Px activity in erythrocytes were significantly elevated in vitamin B₆-supplemented rats compared with vitamin B₆-deficient rats. Se levels in muscle and heart were significantly lower in vitamin B₆-deficient groups fed Na₂SeO₃ than in vitamin B₆-supplemented groups. Vitamin B₆-deficient rats fed selenomethionine had higher Se levels in muscle, heart, spleen, liver, and kidneys than vitamin B₆-supplemented rats. Activity of GSH-Px in muscle, heart, and spleen was significantly lower in vitamin B₆-deficient groups than in vitamin B₆-supplemented groups, regardless of form of Se. A significant decrease of GSH-Px in liver was observed in vitamin B₆-deficient rats fed selenomethionine compared with vitamin B₆-supplemented rats, whereas no significant decrease was observed in those fed Na₂SeO₃. These results suggest that vitamin B₆ is involved in the distribution and transportation of Se in body and the metabolism of selenomethionine in liver.     

Delta 6-desaturase activity in liver microsomes of rats fed diets enriched with cholesterol and/or omega 3 fatty acids.

A glycoprotein antigen was purified from human brain by immunoaffinity chromatography using the 44D10-monoclonal IgG, and its chemical nature was investigated. The yield of antigen was estimated at 91% and a 4340-fold purification was obtained relative to the white-matter homogenate. The antigen preparation from brain was further purified by preparative SDS/polyacrylamide-gel electrophoresis (PAGE) to obtain a glycoprotein with an Mr of 80,000 consisting of a single polypeptide. Amino acid analyses revealed a composition which was high in acidic and neutral amino acids, and low in basic residues. The presence of both glucosamine and galactosamine suggested that the glycoprotein contained both N- and O-linked glycans. Neutral sugar analyses showed that fucose, galactose and mannose were present. An assay for sialic acid determined that there were approximately 20 mol of sialic acid per mol of glycoprotein. Chemical cleavage of oligosaccharides by trifluoromethanesulphonic acid followed by SDS/PAGE showed that carbohydrate accounted for 25,000 of the 80,000-Mr glycoprotein.     

Effects of zinc and/or iron deficiency on rectal temperature in rats

O'Dell et al. reported that rectal temperature was decreased by zinc deficiency in rats. However, it is not known whether a combined deficiency of zinc and iron affects rectal temperature. Forty 4-wk-old male Sprague-Dawley rats were assigned into four dietary treatment groups of 10 rats each for the 4-wk study: zinc-deficient group (4.5 mg Zn and 35 mg Fe/kg diet; −Zn), iron-deficient group (30 mg Zn/kg diet, no supplemental iron; −Fe), zinc/iron-deficient group (4.5 mg Zn/kg diet, no supplemental iron; −Zn−Fe), and control group (AIN-93G; Cont). At d 24–27, the rectal temperature was determined. The rectal temperature of the −Zn group was significantly lower than the Cont group. The rectal temperature of the −Zn−Fe group was similar to that of the Cont group, although thyroid-stimulating hormone and total thyroxin concentrations were the lowest in the −Zn−Fe group among all groups. The pattern of the plasma nitrate/nitrite concentrations across groups was similar to rectal temperature. Although observation of the rectal temperature is not conclusive, the balance between zinc and iron intake seems to determine the body temperature set point. These results suggest that the thermogenic effect of thyroid hormones is not throught to influence the paradoxical maintenance of rectal temperature in combined deficiency of zinc and iron.     

Increased plasma pyridoxal-5′-phosphate when alkaline phosphatase activity is reduced in moderately zinc-deficient rats

It is generally believed that the zinc metalloenzyme alkaline phosphatase is required to hydrolyze phosphorylated forms of vitamin B-6 prior to their use. To test this hypothesis, rats were fed a liquid diet containing either adequate or moderately low zinc during gestation and lactation. Zinc deficiency was produced in dams evidenced by significant reductions in zinc concentration of plasma (49%), liver (25%), and femur (24%), and plasma alkaline phosphatase activity (48%). Plasma pyridoxal-5′-phosphate (PLP), which significantly increased (61%) in these same rats, was negatively correlated (r=−0.74,P<0.02) with plasma alkaline phosphatase activity. Maternal liver PLP concentration was unaffected by zinc status. The zinc and vitamin B-6 relationship seen in dams was less observable in offspring. Stimulation of erythrocyte alanine aminotransferase activity by exogenously added PLP in vitro tended to be higher in both moderately zinc-deficient mothers and their offspring, but the difference was not significant. Our results support the hypothesis that alkaline phosphatase activity is required for the hydrolysis of plasma PLP. Our results also suggest that zinc status as alkaline phosphatase activity should be defined in an individual if plasma PLP is to be used as an indicator of vitamin B-6 status.     

Plasma lipoprotein cholesterol and triglycerides and lipoprotein lipase activity in epididymal white adipose tissue of rats fed high sucrose or high corn oil diets

The present study was undertaken to compare plasma lipoprotein lipid composition, as well as white adipose tissue lipoprotein lipase activity, in rats fed purified diets high in either sucrose or corn oil. The experimental diets (65% of calories as sucrose or corn oil, 15% as the opposite nutrient, and 20% as casein) were given ad libitum for 4 weeks. An additional group was fed a nonpurified diet as a reference diet. Both sucrose and oil diets were spontaneously consumed in isocaloric amounts by the animals. Despite energy intakes that were 35% lower than that of the reference group, the sucrose and oil groups exhibited final body weights that were only 6 and 9% lower, respectively, than that of the reference group, and accumulated more fat in the epididymal depots. Postprandial as well as fasting total cholesterol levels were similar in the sucrose and oil groups, while the high-density lipoprotein to total cholesterol ratio was highest in the animals fed corn oil. In both the fasted and fed states, plasma total triglyceride levels were 73% higher in the sucrose group than in the corn oil group. The largest triglyceride differences due to diet were observed in the chylomicron + very-low-density lipoprotein fraction. The oil-fed rats accumulated large amounts of triglycerides in their livers. Postprandial lipoprotein lipase activity in epididymal adipose tissue was almost twice as high in the sucrose group as in the oil group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cadmium accumulation, zinc status, and mineral bioavailability of growing rats fed diets high in zinc with increasing amounts of phytic acid

Five groups of individually housed albino rats (n=7, initial average weight=48 g) were fed diets based on egg albumen and cornstarch (basal diet 8.2 g Ca, 6.0 g P, 0.7 g Mg, 225 mg Zn, 150 mg Fe, 60 mg Mn, 8 mg Cu, and 5 mg Cd) over a 4-wk period. Group I (control) was fed the basal diet free of phytic acid (PA). In groups II, III, IV, and V, cornstarch was replaced by 3.5, 7.0, 10.5, and 14.0 g sodium phytate/kg diet, respectively. Daily gain, feed efficiency, Zn status (Zn in plasma, femur, testes, liver and kidneys, activity of the plasma alkaline phosphatase) and apparent absorption of Zn, Fe, Cu, and Mn remained unchanged by the different dietary treatments. PA decreased apparent Mg absorption significantly and apparent absorption of Ca in tendency. Increasing the amount of phytate caused a corresponding enhancement of amount of the digestible P. Cd accumulation in the liver was not significantly altered, and kidney Cd accumulation slightly increased owing to PA. In conclusion, it was shown that under conditions of high dietary Zn, PA had only little effect on the carryover of Cd in growing rats.     

Testicular atrophy, zinc concentration, and angiotensin-converting enzyme activity in the testes of vitamin a-deficient rats

Angiotensin-converting enzyme (ACE) as a part of the renin angiotensin system (RES) regulates blood pressure and fluid and electrolyte homeostasis, and the enzyme is considered to have a function in reproduction. Reduced enzyme activities have been observed in atrophied testes as a results of zinc and pituitary deficiencies. Vitamin A deficiency causes atrophy of testes. The present study was conducted on three groups of male, 3-wk-old, Wistar rats. After 54 d of the experimental period, testicular weights of the vitamin A-deficient rats (Agroup, allowed free access to vitamin Adeficient diet) was significantly lower than its pair-fed, PF (given restricted amount control diet) and A+ (allowed free access to control diet) groups. Zinc concentrations and both soluble and particulate ACE activities in the testes of vitamin A-deficient rats (Agroup) were significantly lower than the other two groups. No significant differences were observed regarding zinc concentration, particulate ACE, and total ACE activities in the testes of PF and A+ groups. Vitamin A deficiency did not significantly affect the enzyme activity in the lung. From the observations of the present study, we speculate that testicular atrophy in vitamin A deficiency may have resulted from lower zinc concentration and decreased ACE activity in that organ.     

Portal-drained viscera and hepatic fluxes of branched-chain amino acids do not account for differences in circulating branched-chain amino acids in rats fed arginine-deficient diets

Summary Concentrations and fluxes of amino acids across the portal-drained viscera (PDV) and liver were assessed in rats fed a meal of one of three arginine-deficient diets containing either alanine or the arginine precursors, ornithine or citrulline. A previous report included findings of seven arginine-related amino acids and indicated that only the citrulline-containing diet protected blood arginine concentrations. In the present report we extend these findings and note that the concentrations and fluxes of the non-arginine-related amino acids showed remarkable consistency across diet groups. However, total branched-chain amino acid (BCAA) concentrations of arterial blood were higher in rats fed the - Arg/+ Ala and the - Arg/+ Orn diets than in rats fed the control (+ Arg) diet. The elevated BCAA correlated with higher circulating concentrations of other essential amino acids but were inversely correlated with arginine concentrations. PDV and hepatic fluxes of BCAA were not different across diet groups, indicating that amino acid absorption and hepatic utilization of BCAA were generally comparable across diet groups. Hepatic concentrations of 14 of 22 measured amino acids, including total BCAA, were correlated with their arterial concentrations. The circulating concentrations and net PDV and hepatic fluxes of rats fed the control diet were comparable to our previous observations in fed rats and illustrate the role of the liver in utilization of diet-derived essential amino acids.Abbreviations PDV portal-drained viscera - BCAA branched-chain amino acids - SSA 5-sulfosalicylic acid - PBF portal blood flow - HBF hepatic blood flow - SELSM pooled standard errors of least squares means - TAA total amino acids - NEAA nonessential amino acids - EAA essential amino acids - LNAA large neutral amino acids Mention of a trade name, proprietary product or specific equipment does not constitute a guarantee by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.