Effects of stress on amino acids and related compounds in various tissues of fasted rats

The purpose of this study was to examine the effect of stress on the free amino acid pattern of plasma and various organs. Two groups of rats were deprived of food, for 24 hrs. One group was sacrificed after this time (fasting control representing mostly free endogenous amino acids) and the second group was first restrained in wire cages for 120 min before being sacrificed (fasting stress representing mostly the effects of stress on endogenous free amino acids). A third group had free access to food and was sacrificed at the same time (fed control representing mostly free amino acids absorbed from the gut and endogenous free amino acid metabolism). Fasting (as compared to fed controls) reduced alanine and arginine but increased ethanolamine, glutamic acid and glutamine in the plasma; increased ethanolamine, phosphoethanolamine and glutamic acid in the liver; increased carnosine, glutamic acid, phosphoethanolamine and glutamine in the ventricle; increased oxidized glutathione in the aorta; decreased alanine, aspartic acid, glutamic acid, leucine and methionine and increased glutamine in the pancreas; and decreased arginine in skeletal muscle. Fasting plus stress (as compared to fasting controls) reduced alanine and glutamine in the plasma; increased methionine in the liver; increased ethanolamine, GABA, and glutamic acid in the aorta; reduced arginine, glutamic acid, glutamine, leucine and methionine but increased ethanolamine in the ventricle; reduced ammonia and ethanolamine but increased histidine, isoleucine, leucine, lysine, phenylalanine, tyrosine and valine in the pancreas; and reduced ammonia in skeletal muscle. Fasting plus stress affects the amino acid composition of plasma and various of tissues but effects seen were individually different and strongly substance and tissue specific. Plasma changes did not coincide with tissue changes. Changes in the endogenous pattern of amino acids and related compounds in response to stress could be first indications of stress induced organ pathology.     

Urinary excretion of amino acids in normal and cystinuric dogs

The 24-h urine excretion of 20 amino acids was investigated in 24 cystinuric and 15 normal dogs. The diagnosis of cystinuria was based on infrared spectroscopy of removed uroliths, which in all cases were composed of pure cystine. Seven of 24 cystinuric dogs showed normal cystine excretion compared to normal dogs, and four of 24 dogs showed normal total amino acid excretion. In contrast to earlier investigations, almost half of the cystinuric dogs (46%) showed elevated excretion of five or more amino acids. Isolated cystinuria, or isolated dibasic amino aciduria was not found. Compared to normal dogs, the cystinuric dogs showed a significantly (P < 0.05) increased excretion of cystine, arginine, lysine, cystathionine, glutamic acid, threonine and glutamine. There was a significant correlation (P < 0.05) between the urinary excretion of cystine and 10 other amino acids, with the highest correlation found (P < 0.001) for arginine, lysine, cystathionine, ornithine and 1-methyl-histidine. Three patterns of amino acid excretion could be identified: (1) increased excretion and a significant correlation with cystine for the three dibasic amino acids (lysine, arginine and ornithine), compatible with a common reabsorption mechanism as shown in man. This pattern was also found for cystathionine and glutamic acid, which might indicate a relation in metabolism or transport; (2) increased excretion but no correlation with cystine for glutamine, threonine and citrulline; (3) good correlation with cystine, but no increased excretion for 1-methyl-histidine, phenylalanine, 3-methyl-histidine, leucine and alanine. The great variation in urinary cystine excretion suggests that factors other than the excretion of cystine must be considered as causes of cystine urolith formation. For example, cystinuric dogs were found to have lower diuresis than normal dogs and produced urine with higher cystine concentration thereby increasing the risk of cystine urolith formation.     

Age-specific distribution of plasma amino acid concentrations in a healthy pediatric population

Reference values were determined for 23 plasma free amino acids from measurements done in 148 healthy children ranging from 0 to 18 years of age. Amino acid analysis was performed by ion-exchange chromatography. We propose a graphic form of presenting the age-specific distribution of plasma amino acid concentrations where the 10th, 50th, and 90th quantiles are illustrated. Although each amino acid possesses its own pattern of distribution, we can identify five different profiles. Nine amino acids (alanine, arginine, asparagine, methionine, ornithine, phenylalanine, proline, threonine, and tyrosine) demonstrate a decrease in their concentrations during the first year of life; their concentrations then tend to increase throughout childhood and adolescence. Nine others (cystine, glutamine, glycine, histidine, isoleucine, leucine, lysine, tryptophan, and valine) show a steady increase throughout infancy, childhood, and adolescence. Five amino acids (aspartic acid, citrulline, glutamic acid, serine, and taurine) do not follow these two common profiles. For the first time, quantile curves are produced to illustrate the age-dependent variation of amino acid concentrations from infancy to adulthood. This alternative way of presenting amino acid concentrations may facilitate the follow-up of patients with inborn errors of amino acid metabolism.     

Optimum amino acid complement for protein synthesis by rat mammary cells in tissue culture

The amino acid requirement of rat mammary cells for milk protein synthesis was investigated in dispersed cell culture. A three-dimensional central composite design utilizing three variables (X1 = lysine; X2= methionine, valine, and arginine; X3 = isoleucine, tryptophan, threonine, phenylalanine, and histidine) at five concentrations each, was duplicated twice with mammary cells from lactating Sprague-Dawley rats. The optimum combination of amino acids for maximum milk protein synthesis from multiple regression models was X1 15.0-, X2 4.5-, and X3 1.5-fold their quantities in Eagle's minimal essential medium with leucine, tyrosine, cystine, and glutamine at the base 1-fold in the medium.     

Intermediate filament cytoskeletal proteins associated with bovine lens native membrane fractions

1. Arginine can be produced in the kidney from citrulline. An important source of circulating citrulline is the intestinal breakdown of glutamine. Consequently, partial enterectomy leads to decreased plasma citrulline levels. The aim of the present study was to investigate the effect of diminished arterial citrulline levels on renal arginine production and total-body free arginine pools.2. Renal amino acid metabolism was studied 24 h after 75% small bowel resection in rats fasted overnight (16 h) (n=12; total fast 40 h). Sham-operated (n=9) and non-operated 16-h and 40-h fasted controls were studied in parallel (n=8/n=7). During anaesthesia, L-(2, 3-3H)-arginine and para-aminohippuric acid were infused until steady state. Subsequently, arterial and renal venous blood samples were taken. Concentrations of para-aminohippurate and amino acids and specific activity of arginine and citrulline were measured to calculate renal plasma flow, net renal uptake or release, and unidirectional influx or efflux of arginine and citrulline, as well as whole-body arginine turnover.3. Arterial citrulline was decreased in enterectomized rats compared with sham-operated rats (23+/-3 versus 44+/-6 microM). Net renal citrulline uptake and arginine release were almost stoichiometric (-36+/-7 and 38+/-6 nmol.min-1. 100 g-1 body weight respectively in sham-operated rats) and were both diminished by 50% in enterectomized versus sham-operated rats. In all groups, net renal arginine production accounted for less than 10% of whole-body rate of arginine appearance (488 nmol.min-1.100 g-1 body weight in the sham group). Despite decreased net renal citrulline consumption and renal arginine production in enterectomized rats, whole-body rate of arginine appearance and arterial arginine did not change significantly.4. In conclusion, net renal arginine production is reduced 24 h after 75% enterectomy in fasted rats. However, this does not have important effects on whole-body arginine production.     

Maternal dietary protein deficiency decreases amino acid concentrations in fetal plasma and allantoic fluid of pigs

This study was conducted to test the hypothesis that maternal dietary protein deficiency decreases amino acid availability to the fetus, thereby contributing to retarded fetal growth. Primiparous gilts selected genetically for low or high plasma total cholesterol concentrations (low line and high line, respectively) were mated, and then fed 1.8 kg/d of isocaloric diets containing 13% or 0.5% crude protein. At d 40 or 60 of gestation, they were hysterectomized, and maternal and fetal blood samples as well as amniotic and allantoic fluids were obtained for analyses of amino acids, ammonia and urea. Dietary protein restriction decreased (P < 0.05) the following: 1) maternal plasma concentrations of urea at d 40 and 60 of gestation; 2) fetal plasma concentrations of alanine, arginine, branched-chain amino acids (BCAA), glutamine, glycine, lysine, ornithine, proline, taurine, threonine and urea at d 60 of gestation; 3) amniotic and allantoic fluid concentrations of urea at d 40 and 60 of gestation; and 4) allantoic fluid concentrations of alanine, arginine, BCAA, citrulline, cystine, glycine, histidine, methionine, proline, serine, taurine, threonine and tyrosine at d 40 of gestation, in gilts of both genetic lines. At d 60 of gestation, protein deficiency decreased (P < 0.05) allantoic fluid concentrations of arginine, cystine, glycine, taurine and tyrosine in low line gilts and of cystine, glutamine, ornithine, serine, taurine and tyrosine in high line gilts. Low line and high line gilts also differed remarkably in allantoic fluid concentrations of arginine, glutamine, ornithine and ammonia at d 40 and 60 of gestation. Our results suggest the following: 1) protein-deficient gilts maintain maternal plasma concentrations of amino acids by mobilizing maternal protein stores and decreasing oxidation of amino acids during the first half of gestation; 2) protein deficiency may impair placental transport of amino acids from the maternal to the fetal blood; and 3) low line and high line gilts differ in fetal amino acid metabolism. Decreases in concentrations of the essential and nonessential amino acids in the fetus may be a mechanism whereby maternal dietary protein restriction results in fetal growth retardation.     

Acetohydroxy acid synthase and threonine deaminase activities, and the biosynthesis of isoleucine-leucine-valine in Streptococcus bovis

Acetohydroxy acid synthase (AHAS) and threonine deaminase (TD) activities were found in Streptococcus bovis and shown to be involved in the biosynthesis of the branched chain amino acids isoleucine, leucine and valine. Apparent lack of repression of AHAS synthesis by the end-products and reduced sensitivity of S. bovis growth to analogues of the branched chain amino acids suggested that secretion of isoleucine, leucine and valine in the growth medium may be a consequence of the regulatory features of AHAS. A glycyl-leucine-resistant mutant with reduced TD activity secreted a reduced amount of isoleucine and an increased amount of valine, which might be a result of the reduced rate of synthesis of the isoleucine precursor alpha-ketobutyrate and of a consequent preferential carbon flow through the valine branch of the pathway.     

Metabolic evaluation of cultured porcine hepatocyte monolayers in human plasma from hepatic failure patients--basic study on development of a bioreactor in hybrid artificial liver

In order to develop a functional bioreactor for hybrid artificial liver, function of cultured porcine hepatocyte monolayers in human plasma from hepatic failure patients (group III, n = 5) was investigated. Culture media, Leibovitz L-15 medium (group I, n = 7) and normal human plasma (group II, n = 3), were used as controls. Morphologically, no degeneration of porcine hepatocytes in hepatic failure plasma was observed for 5 days in culture. Levels of ureogenesis showed no significant difference against the controls at day 1, 2, 5 in culture, but the level at day 3 was significantly higher than that of group II. Levels of gluconeogenesis showed a close tendency as those of ureogenesis, but the level at day 3 was significantly lower than that of group I. Levels of intracellular DNA contents, showing between 1.85 +/- 0.39 and 1.35 +/- 0.05 microgram/cm2, were compatible with those of controls during first three days in culture, but level of group III at day 5 was significantly higher than that of group I. After incubation of porcine hepatocyte in hepatic failure plasma, the amount of valine, leucine, isoleucine, glutamine, arginine, and citrulline was significantly decreased. Elevated phenylalanine and tyrosine were also decreased, but Fischer's ratio, the ratio of branched chain amino acid against aromatic amino acids, was not significantly increased. Data obtained by this investigation showed that cultured porcine hepatocytes held proper hepatic function in the hepatic failure plasma. It is concluded that culture porcine hepatocyte monolayers were a promising candidate for a bioreactor of a hybrid artificial liver.     

Hemostatic properties of tissues of the gastrointestinal tract in thyrotoxicosis and during parenterl nitrogenous feeding

Using diets based on rat amino acid requirements, containing 2.0% nitrogen and 4.1 digestible kcal/g, the dietary levels of ten essential amino acids required for normal post-weaning growth of Swiss X Carworth Farms No. 1 crossbred mice were estimated. The response criteria used were growth rate, dry matter intake, energy and protein contents of body weight gain, protein efficiency ratio and apparent biological value. Maximum responses were obtained when the dietary dry matter contained less than or equal 0.3% arginine, 0.2% histidine, 0.4% isoleucine, 0.7% leucine, less than or equal 0.4% lysine, 0.5% methionine, less than or equal 0.4% phenylalanine, 0.4% threonine, less than or equal 0.1% tryptophan and 0.5% valine.     

Analysis of developing enamel of the rat. II. Electrophoretic and amino acid studies

Amino-acid analyses showed that proline, glutamic acid and leucine were the most common amino acids in immature or developing enamel and in each of its fractions (i.e., in the 1st and 14th water-extractable fractions of a sequential series of extractions, EDTA-water soluble and water-insoluble fractions. The immature enamel and its 1st and 14th water-extractable fractions were similar in their proportions of the basic amino acids (lysine, histidine and arginine), the beta-hydroxylated aliphatic amino acids (valine, leucine, and isoleucine). On the other hand, the immature enamel differed from the water-extractable fractions chiefly in its relative content of aspartic acid, glutamic acid, alanine, proline, glycine, tyrosine and methionine. Also the 1st water-extractable fraction differed from the 14th in its amino-acid profile. tthe EDTA-water-soluble fraction most closely resembled the 14th water-extractable fraction except for its proportion of arginine and alanine residues. Although with polyacrylamide gel electrophoresis the EDTA-water-soluble and the water-extractable fractions exhibited companion bands (at least 7 peaks were evident at pH 9.3) they differed decidely as to which band was the most prominent. The water-insoluble fractions compared with any of the soluble fractions or with immature enamel showed a higher percent of serine, threonine, glycine, aspartic acid, alanine, valine, lysine, and arginine but relatively less glutamic acid, proline, methionine and histidine. Neither hydroxyproline nor hydroxylsine were detected in any of the samples.     

Endogenous synthesis of arginine plays an important role in maintaining arginine homeostasis in postweaning growing pigs

This study was conducted to determine whether endogenous synthesis of arginine plays a role in regulating arginine homeostasis in postweaning pigs. Pigs were fed a sorghum-based diet containing 0. 98% arginine and were used for studies at 75 d of age (28.4 kg body weight). Mitochondria were prepared from the jejunum and other major tissues for measuring the activities of Delta1-pyrroline-5-carboxylate (P5C) synthase and proline oxidase (enzymes catalyzing P5C synthesis from glutamate and proline, respectively) and of ornithine aminotransferase (OAT) (the enzyme catalyzing the interconversion of P5C into ornithine). For metabolic studies, jejunal enterocytes were incubated at 37 degrees C for 30 min in Krebs-Henseleit bicarbonate buffer containing 2 mmol/L L-glutamine, 2 mmol/L L-[U-14C]proline, and 0-200 micromol/L gabaculine (an inhibitor of OAT). The activities of P5C synthase, proline oxidase and OAT were greatest in enterocytes among all of the tissues studied. Incubation of enterocytes with gabaculine resulted in decreases (P < 0.05) in the synthesis of ornithine and citrulline from glutamine and proline. When gabaculine was orally administered to pigs (0.83 mg/kg body weight) to inhibit intestinal synthesis of citrulline from glutamine and proline, plasma concentrations of citrulline (-26%) and arginine (-22%) decreased (P < 0.05), whereas those of alanine (+21%), ornithine (+17%), proline (+107%), taurine (+56%) and branched-chain amino acids (+21-40%) increased (P < 0.05). On the basis of dietary arginine intake and estimated arginine utilization, the endogenous synthesis of arginine in the 28-kg pig provided >/=50.2% of total daily arginine requirement. Taken together, our results suggest an important role for endogenous synthesis of arginine in regulating arginine homeostasis in postweaning growing pigs, as previously shown in neonatal pigs.     

Amino acid substitutions in the C-terminal regulatory domain disrupt allosteric effector binding to biosynthetic threonine deaminase from Escherichia coli

Shifts in the sigmoidal kinetics of allosteric threonine deaminase promoted by isoleucine and valine binding control branched chain amino acid biosynthesis in Escherichia coli. A highly conserved alpha-helix in the C-terminal regulatory domain of the tetrameric enzyme was previously implicated in effector binding and feedback inhibition. Double (447, 451) and triple (447, 451, 454) alanine replacements for the conserved amino acids leucine 447, leucine 451, and leucine 454 in this region yield enzyme variants that show increased sigmoidality in steady-state kinetics, and which are less sensitive to the allosteric modifiers isoleucine and valine. Equilibrium binding studies using fluorescence, enzyme kinetic, and calorimetric approaches indicate that the enzyme variants possess reduced affinity for isoleucine and valine, and suggest that heterotropic ligands can bind to the same site to promote their different effects. The increase in sigmoidal kinetics for the mutants relative to wild-type threonine deaminase may be attributable to the elimination of L-threonine binding to the effector sites, which activates the wild-type enzyme. Enzyme kinetic data and isotherms for active site ligand binding to the mutants can be analyzed in terms of a simple two-state model to yield values for allosteric parameters that are consistent with previous estimates based on an expanded two-state model for homotropic cooperativity for threonine deaminase.     

Essential and nonessential amino acid composition of pigs from birth to 145 kilograms of body weight, and comparison to other studies

The amino acid composition of the body components (carcass, hair, whole blood, and a composite of the other body tissues) were determined from a total of 81 crossbred pigs at 10 weight intervals from birth to 145 kg body weight. Body component amino acid compositions (g/100 g protein) were multiplied by their respective protein contents, resulting in calculated whole-body amino acid compositions. From 8.5 to 145 kg body weight, the amino acid compositions were similar within each body component but differed between body components. There was a higher concentration of carcass lysine, arginine, and histidine (P < .01) in the carcass, and isoleucine (P < .12), threonine (P < .15), and methionine (P < .08) tended to be higher than in the composite of the other body tissue. Whole blood was, however, higher in leucine, valine, and lysine, and hair was higher in cystine than the carcass. The relative concentration of lysine in the whole body increased to about 37 kg body weight and reached a plateau, whereas the other essential amino acids increased to 8.5 kg and then reached a plateau. Tryptophan, however, decreased from birth to 8.5 kg and then remained at a similar concentration to 145 kg body weight. Whole-body amino acid composition of pigs in our study was generally similar to that noted in other scientific reports, but there was a wide variation in amino acid values between studies.     

Altered L-DOPA systems for blood pressure regulation in the lower brainstem of spontaneously hypertensive rats

Recent findings have enhanced our understanding of the roles played by the L-DOPA system in the baroreceptor reflex and in blood pressure regulation in the lower brainstem. L-DOPA is probably a neurotransmitter of primary baroreceptor afferents terminating in depressor sites of the nucleus tractus solitarii (NTS). It also seems to be a neurotransmitter in depressor sites of the caudal ventrolateral medulla (CVLM) and in pressor sites of the rostral ventrolateral medulla (RVLM) of normotensive Wistar rats. We have explored whether or not presynaptic and postsynaptic functions of the L-DOPA system in these areas are altered to maintain hypertension in adult spontaneously hypertensive rats, as compared with age-matched Wistar Kyoto rats. In this review article, we survey the roles of the L-DOPA system in the baroreceptor reflex and in blood pressure regulation in the rat lower brainstem.     

Modulation of pentylenetetrazol-induced seizure activity by branched-chain amino acids and alpha-ketoisocaproate

Branched-chain amino acids, and mainly leucine act as nitrogen donors in the cerebral glutamate-glutamine cycle, thereby reducing brain excitability. Rats equipped with cortical electrodes received 300 mg/kg of leucine, isoleucine, valine or the ketoacid of leucine, alpha-ketoisocaproate at 2 h before the induction of seizures by 40 mg/kg pentylenetetrazol. Control groups received saline or a commercial mixture of amino acids, Vamine(R). Leucine and isoleucine increased the latency to absence-like and tonic-clonic seizures but did not influence the duration of the tonic-clonic seizure. Vamine(R), valine and alpha-ketoisocaproate had no effect. These data are consistent with the role of leucine in buffering brain glutamate concentration.     

Stoichiometry, kinetics, and regulation of glucose and amino acid metabolism of a recombinant BHK cell line in batch and continuous cultures

Batch and continuous cultures were carried out to study the stoichiometry, kinetics, and regulation of glucose and amino acid metabolism of a recombinant BHK cell line, with particular attention to the metabolism at low levels of glucose and glutamine. The apparent yields of cells on glucose and glutamine, lactate on glucose, and ammonium on glutamine were all found to change significantly at low residual concentrations of glucose (< 5 mmol/L) and glutamine (< 1 mmol/L). The uptake rates of glucose and glutamine were markedly reduced at low concentrations, leading to a more effective utilization of these nutrients for energy metabolism and biosynthesis and reduced formation rates of lactate and ammonium. However, the consumption of other amino acids, especially the essential amino acids leucine, isoleucine, and valine and the nonessential amino acids serine and glutamate, was strongly enhanced at low glutamine concentration. Quantitatively, it was shown that the cellular yields and rates associated with glucose metabolism were primarily determined by the residual glucose concentration, while those associated with glutamine metabolism depended mainly on the residual glutamine. Both experimental results and analysis of the kinetic data with models showed that the glucose metabolism of BHK cells is not affected by glutamine except for a slight influence under glucose limitation and glutaminolysis not by glucose, at least not significantly under the experimental conditions. Compared to hybridoma and other cultured animal cells, the recombinant BHK cell line showed remarkable differences in terms of nutrient sensitivity, stoichiometry, and amino acid metabolism at low levels of nutrients. These cell-line-specific stoichiometry and nutrient needs should be considered when designing an optimal medium and/or feeding strategy for achieving high cell density and high productivity of BHK cells. In this work, a cell density of 1.1 x 10(7) cells/mL was achieved in a conventional continuous culture by using a proper feed medium.     

Protection of PC12 cells glutathione peroxidase in L-DOPA induced cytotoxicity

L-DOPA may cause side-effects during the treatment of Parkinson's disease. We investigated the role of glutathione peroxidase (GSHPx) in cellular defense against L-DOPA cytotoxicity. A line of PC12 cells overexpressing GSHPx with plasmid pRc/CMV-GSHPx was established and stable transfectants overexpressing GSHPx were used for this study. GSHPx activity was found to be 1.5-fold higher in GSHPx-transfectants than in mock-controlled transfectants. Transfectants over expressing GSHPx were also significantly more resistant to exposure to either L-DOPA or t-butyl hydroperoxide than mock-transfected cells. Results suggested that L-DOPA may cause neuronal cell death by an oxidative pathway and GSHPx may play an important role in cellular defense against oxidative stress.     

L-DOPA exacerbates amphetamine-induced dopamine depletion

Administration of L-DOPA to Parkinson patients has been suggested to exacerbate "functional denervation" of the nigrostriatal system. Therefore, experiments were conducted to determine if L-DOPA combined with the DOPA decarboxylase inhibitor, Ro4-4602 (benserazide hydrochloride) would potentiate amphetamine-induced neurotoxicity. Mice received two injections of saline or benserazide + L-DOPA (25.0 or 100.0 mg/kg) interspersed with four injections of amphetamine (15.0 mg/kg) at 2-h intervals. Significant depletion of striatal dopamine, DOPAC, and HVA was evident 1 wk following amphetamine administered with or without 25.0 mg/kg L-DOPA + benserazide, whereas 100.0 mg/kg L-DOPA + benserazide potentiated amphetamine-induced depletion of striatal dopamine (17 vs 28% of control values). This enhanced toxicity may be consequent to increased dopamine turnover following L-DOPA (360 vs 231%), a situation akin to that observed in compromised dopaminergic nigrostriatal systems of parkinsonian patients. Furthermore, striatal 5-HT was not altered by amphetamine alone, whereas concurrent administration of L-DOPA/ benserazide depleted 5-HT to 82% of control values. No changes were evident in the frontal cortex following amphetamine with or without concurrent L-DOPA/benserazide; however, L-DOPA/benserazide administered alone reduced 5-HT and 5-HT turnover to 58% of control values.     

Quantitative evaluation of the blood-brain barrier capacity to form dopamine from circulating L-DOPA

The ability of the blood-brain barrier to form dopamine from increasing doses of systemically administered L-DOPA has been studied in rats by a combination of chemical determination of dopamine, and histochemical and cytofluorometric measurements of L-DOPA and dopamine. The break-through of L-DOPA from the circulation into the brain parenchyma via the enzymatic blood-brain barrier was estimated by comparing the amount of newly formed dopamine in the caudate nucleus-putamen and in the cerebellum. The capillaries were found to efficiently trap L-DOPA in their walls, and an upper limit was reached (at an administered i.p. dose of 100 mg/kg of L-DOPA). It could be estimated that approximately 3% of the total dose of L-DOPA given was decarboxylated by the blood-brain barrier. The possible influence by the regional differences in perfusion of the two regions seen after administration of L-DOPA was ruled out in measurements of local cerebral blood flow using the 14C-ethanol technique.     

Plasma amino acid profile in relation to arterial ketone body ratio in surgical patients

A total of 357 plasma amino acid profiles from 93 surgical patients were statistically analyzed in relation to the changes in arterial ketone body ratio, which reflects the hepatic mitochondrial redox state. When the arterial ketone body ratio was above 0.7, all plasma amino acid levels were within the normal range. When it was between 0.7 and 0.4, plasma levels of aspartate, glutamate, valine, isoleucine, leucine, ornithine, and arginine decreased, and plasma levels of tyrosine, phenylalanine, proline, and methionine increased. Furthermore, when it was below 0.4, almost all plasma amino acids markedly increased. These results indicate that arterial ketone body ratio accurately reflects the alterations in plasma amino acid profile, and can serve as an indicator for providing nutritional support by amino acid supplement in surgical patients.