Young rats were used in bioassays designed to assess the protein quality and tryptophan as well as cystine adequacy of the enteral product TwoCal-HN that was either freshly prepared or had been stored (nonrefrigerated) in a warehouse for 10 mo (i.e., beyond shelf life). Based upon supplementation studies, cystine was ...

Rats were fed toxic levels of methionine with or without simultaneous dietary supplements of glycine and serine. Feed intake, growth rate, and metabolite concentrations in intestine, plasma, liver, skeletal muscle, and kidneys were monitored. Both toxic amounts of methionine and supplemental glycine and serine affected the tissue distribution of several ...

Dietary energy restriction has been a widely used means of experimentally extending mammalian life span. We report here that lifelong reduction in the concentration of a single dietary component, the essential amino acid L-methionine, from 0.86 to 0.17% of the diet results in a 30% longer life span of male ...

The uptake of the beta-amino acid taurine by rat renal brush border membrane vesicles (BBMV) adapts to changes in dietary sulfur amino acid intake. Initial rate Vmax "upregulates" after ingestion of a low methionine and taurine diet (LTD) and "downregulates" after a high taurine diet (HTD). This is reflected in ...

The effect of long-term dietary taurine insufficiency on reproductive function was studied in adult female domestic cats (n = 11). Cats were time-mated during taurine-deficient (6 months) and refed (6 months) states, and the outcome of ovulatory cycles and breeding was analysed. Serum progesterone and relaxin concentrations were evaluated in ...

Urinary nitrate (NO3) is the stable end product of nitric oxide, which is formed, in turn, from a guanidino nitrogen of arginine. We have conducted two experiments, each in four healthy adult men receiving a low nitrate diet for 7-10 days, to investigate the in vivo conversion of arginine to ...

The use of the enzyme tryptophan side-chain oxidase, isolated from Pseudomonas XA, was explored in 3 patients with refractory acute lymphocytic leukemia. Patients were given either a low-tryptophan diet or tryptophan-free hyperalimentation, prior to and during therapy. Their plasma, separated by pheresis, was continuously passed through a tryptophan depletion column ...

The effect of meal-induced changes in serum free tryptophan (TRP) levels on brain TRP levels was examined in streptozotocin-diabetic rats. Diabetic rats, fasted overnight, were given free access to a non-protein food containing either no fat or large amounts of fat (45% by weight), and were killed 1, 2 or ...

In pot experiments, S-deficiency decreased the seed weight of rape from 4.30 to 2.44 g/1000 seeds at highest N-level. N/S ratios varied from 5.8 to 45.0 and from 3.7 to 21.6 in ryegrass and kale. S-deficiency tended to decrease the fat(oil) content. In kale and ryegrass, it was increased by ...

A previously undocumented hypokalaemic condition with a cyclical nature, comprising acute bouts of polymyopathy followed by spontaneous recoveries, is described in the cat. Cats being fed a high protein vegetarian diet developed recurrent episodes of polymyopathy, characterised by ventroflexion of the head and neck, stiff forelimb gait, lateral head-resting and ...

1. S-Adenosyl-L-methionine is reported to improve serum liver function tests in chronic liver disease. Because liver disease is complicated by cholesterol deposition in hepatic and extrahepatic membranes, we have assessed whether oral administration of S-adenosyl-L-methionine to patients with hepatic disease can reverse the cholesterol enrichment of their erythrocytes. 2. The ...

An assay was conducted to determine the efficiency of dietary methionine retention for protein accretion in 14-kg pigs. During an 18-d feeding period, pigs were fed a chemically defined amino acid basal diet [147.7 g protein (N x 6.25)/kg, 14.43 MJ metabolizable energy/kg, 4000 mg L-cystine/kg] containing 1150, 1725 or ...

1. Experiments were conducted independently at two stations to measure the requirement for methionine in chick diets with crude protein (CP) varying in 8 steps from 140 to 280 g/kg diet (experiment 1) or from 90 to 300 g/kg (experiment 2). 2. Protein composition was the same at all protein ...

The effect of methionine or citrate on antioxidant defense system has been studied in urolithic rat. Liver weight and its protein concentration did not change in the rats fed with calculi producing diet (CPD) when compared to normal diet fed rats. Feeding rats along with citrate (c-CPD) or methionine (m-CPD) ...

This study determined whether acetaminophen (ACAP)-induced glutathione depletion was associated with liver lipid peroxide formation, or the concentrations of liver S-adenosylmethionine and S-adenosylhomocysteine in mice fed diets with L-methionine below or at the requirement level (0.25 or 0.5%) for 7 wk. Iron dextran (281 mg/kg body wt) or saline was ...

Between October 1986 and September 1988, 37 cats with moderate to severe idiopathic myocardial failure (dilated cardiomyopathy) were evaluated prospectively. Low plasma taurine concentration and diet history including foods that can cause taurine deficiency were documented in most of the cats. Comparison with a retrospectively studied population of 33 cats ...

Therapeutic use of amiodarone (AD), an effective antiarrhythmic drug, is associated with serious pulmonary toxicity (e.g., fibrosis and phospholipidosis). In the present study, we tested if taurine and/or niacin, which prevent bleomycin-induced lung toxicity, could prevent AD-induced lung toxicity in hamsters. AD alone significantly increased lung hydroxyproline (an index of ...

Plasma taurine and serine decrease following trauma and in severe inflammatory disease. These changes may signify an increase in requirements for sulfur amino acids. We previously demonstrated that cysteine supplementation can restore the impaired ability of rats fed an 8% casein diet to increase hepatic zinc, glutathione (GSH) and protein ...

The effect of an arginine-deficient diet on net flux of amino acids across the portal-drained viscera and across the liver was studied in rats. Blood was obtained after food deprivation and 1 and 2 h after a meal of a 1.0% arginine control diet or an arginine-deficient diet containing 3.4% ...

A 10-year-old cat that was kept on a diet consisting largely of raw liver was evaluated because of lethargy, partial anorexia, and weight loss of several months' duration. The cat's head and neck were rigidly extended, and a hard mass was palpable in the ventral cervical region. Cervical and thoracic ...

Kidneys of adult animals serve as a major biosynthetic source of arginine. Recently, we demonstrated that kidneys of rats infused with citrulline responded to the elevated plasma citrulline concentrations by increasing citrulline uptake and producing greater quantities of arginine. The objective of the present study was to determine the effects ...

Experiments were designed to develop a urinary excretion model for the study of taurine status in adult cats. The time course of changes in urinary taurine excretion in response to alterations in dietary taurine was examined in Experiment 1. Urinary taurine excretion decreased rapidly when cats were switched from a ...

Young rainbow trout were given diets containing graded levels of methionine for 16 wk. Analysis of the weight gain and food efficiency data showed the methionine requirement to be not more than 0.76% of the diet (1.9% of dietary protein). Activities of regulatory enzymes of the transulfuration pathway, methionine adenosyltransferase ...

This study was designed to determine the role of dietary organic and inorganic sulfur on 3'-phosphoadenosine 5'-phosphosulfate (PAPS) homeostasis. Organic sulfur was altered by adding various amounts of methionine (0.15, 0.3, 0.6, or 1.2%) to a sulfhydryl-deficient diet. Inorganic sulfur was altered by providing rats with no sulfate or sulfate ...

The effect of taurine on the serum and liver cholesterol and triglyceride levels was studied in rats fed cholesterol plus cholic acid. Four groups of 4 weeks old rats were fed control diet, hypercholesterolemic diet (HCD), HCD + 1% taurine or HCD + 2% taurine for 8 weeks. Addition of ...

Soft-moist cat foods containing 6-13% propylene glycol (PG) induce Heinz body formation and decreased red blood cell (RBC) lifespan in adult cats in a dose dependent manner. Since kittens eat relatively more food/kg of body weight and must expand their blood volume in addition to replacing senescent RBC, the hematologic ...

Eleven patients with DSM-III-R schizophrenia were entered into a 4-day tryptophan (TRP)-deficient diet. The diet lowered total plasma TRP levels in all patients; during the diet phase, there was a greater than 50% reduction in mean total plasma TRP levels from the pre-diet phase. The low-TRP diet improved performance on ...

The hepatic concentrations of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) and adenosine (Ado) in the rat were examined diurnally and as a function of fasting. Ado concentrations increased continuously throughout the fasting period; concentrations after 2 days of fasting were 7.5-fold higher than control values. Diurnally, the concentration of Ado was highest ...

Ileal fluxes, urinary losses and taurine balance were determined in six taurine-replete and four taurine-depleted cats. Digesta samples collected at the terminal ileum were used to assess ileal flux of taurine. Four diets were tested: a commercial diet in two forms (heat-processed and frozen) and two purified diets containing either ...

We have previously reported that a single meal of an arginine-free diet rapidly induces hyperammonemia in young ferrets and that aspirin administration in conjunction with influenza B infection and arginine-free diet results in clinical and biochemical alterations consistent with Reye's syndrome. The objective of the present study was to test ...

1. Experiments were conducted with laying hens to determine the effects of supplementing 0, 1.0, 2.0 and 3.0 or 4.0 g trp/kg diet to a maize and soyabean meal-based laying ration (basal tryptophan = 1.66 g/kg) on tissue lipid concentrations. 2. Plasma cholesterol, triglycerides and nonesterified fatty acids were increased ...

Although low plasma taurine concentrations have been associated with congestive cardiomyopathy in cats, the cause of taurine depletion in cats consuming adequate quantities of taurine is unknown. Taurine depletion and cardiovascular disease (cardiomyopathy and thromboembolism) developed unexpectedly in 3 of 6 healthy adult cats during a potassium-depletion study. Plasma taurine ...

Myocardial taurine concentrations were measured in cats with cardiac disease and in healthy cats fed diets with various concentrations of taurine. Group 1 was composed of 26 cats with 3 categories of naturally developing cardiac disease: dilatative cardiomyopathy (group 1A), 10 cats; hypertrophic cardiomyopathy (group 1B), 9 cats; and volume ...

Male Wistar rats were fed diets containing supplements of either methionine or cystine from 10 weeks of age and compared to rats fed a control diet or a high protein diet kept under identical conditions. At 11-16 months of age, the aorta and the renal, iliac and caudal arteries of ...

Hypotaurine increased in some tissues, especially in muscle, and urine of rats fed methionine excess diet. The significant depression of the body weight and food intake of rats caused by excess methionine was remarkably alleviated as previous reports and hypotaurine content in muscle and urine increased further by supplement with ...

Cat foods containing propylene glycol (PG) induce Heinz body formation in feline erythrocytes. To further study the hematologic importance of dietary PG, 21 adult cats were allotted to 3 groups of 7 each and fed diets containing 0, 6, or 12% PG on a dry-weight basis. Cats fed PG had ...

The biochemical impairment in the taurine anabolic pathway of the cat has not yet been fully elucidated; however, a number of key enzymes are known to have reduced activity in the cat compared to the rat. There are a series of possible routes resulting in the formation of taurine, one ...

Urinary taurine excretion increases markedly when excess taurine is consumed. Experiments were designed to characterize this response in an attempt to develop an assay system for taurine bioavailability in common cat foods using an adult cat model. Initial studies investigated the time course of changes in urinary taurine excretion in ...

Taurine is a ubiquitous amino sulfonic acid in mammals, present in high concentrations in tissues, including those exposed to elevated levels of oxidants. Experiments were designed to examine the consequences of taurine deficiency on production of ROI in leukocytes isolated from the lungs and blood of cats fed taurine-deficient diets. ...

The reproductive performance and outcome of kittens was determined for female cats fed 0.05, 0.2 or 1% taurine. No adverse effects of high taurine diets were noted in the adults or offspring, and the reproductive performance was slightly better than that of females fed the normal (0.05% taurine) diet. Body ...

The bleomycin (BL)-hamster model of interstitial pulmonary fibrosis (IPF) is generally associated with increased lung lipid peroxidation, measured as malondialdehyde equivalent (MDAE), calcium and collagen content; and superoxide dismutase (SOD), prolyl hydroxylase (PH) and poly(ADP-ribose) polymerase activities. We found that combined treatment with taurine in drinking water (1%) and niacin ...

Two groups of chicks were fed, until they were 3 weeks old, diets supplemented with either DL-methionine (MET) or DL-2-hydroxy-4-methylthiobutanoic acid (HMB). Oxidation to CO2 and uric catabolism of intraperitoneally injected L-[1-14C]MET and DL-[1-14C]HMB were studied comparatively for 8 h. HMB supplementation spares available MET from both oxidative and uric ...

1. Pigs were maintained in air or in an atmosphere of nitrous oxide which dramatically changes the S-adenosyl-L-methionine to S-adenosyl-L-homocysteine ratio in neural tissues. Samples of cerebrospinal fluid, cortex, cerebellum and spinal cord were then extracted and analysed for S-adenosyl-L-methionine and S-adenosyl-L-homocysteine. Regression analyses were carried out on values obtained ...

We have observed a significantly increased content of fats and decreased content of proteins in the liver of experimental rats fed a diet supplemented with 25% casein proteins in comparison with the application of de-fatted soy flour. Casein proteins have a higher content of methionine in relation to cystine than ...

The supplementation of methionine and threonine to a 10% soy protein isolate diet caused sharp decreases in the concentrations of brain tryptophan, serotonin and 5HIAA (5-hydroxyindole acetic acid) (e.g., in the hypothalamus, hippocampus, amygdala, locus coeruleus and brain stem). The serum tryptophan ratio (i.e., the ratio of the serum concentration ...

A study was conducted to determine an optimal time for supplementation of DL-methionine in relation to time of forage intake by mature British breed-type crossbred cows, and two other experiments were conducted to determine whether ruminal ammonia concentration limited changes in disappearance rates in situ and ruminal functions caused by ...

Male rats were fed sulfur and nonsulfur amino acid-supplemented diets, and the response of cysteine sulfinic acid decarboxylase (CSAD) activity was determined. After adaptation to a casein-based basal diet, rats were fed diets containing additions of L-methionine. Hepatic CSAD activity decreased in a dose-dependent manner. Significant depression of CSAD activity ...

The effect of dietary 13-cis-retinoic acid (CRA) on hepatic methionine metabolism was examined in young male rats. Rats were fed a 10% casein diet (controls) or this diet supplemented with L-methionine (10 g/kg diet), with or without the addition of CRA (100 mg/kg diet), for 10 d. Methionine-supplemented rats exhibited ...

The reproductive performance of female cats is severely affected by dietary taurine deficiency resulting in excessive reproductive wastage, including frequently resorbed or aborted fetuses and stillborn or low birth-weight live kittens. These studies were performed using female cats fed a completely defined purified diet (taurine-free) alone or supplemented with taurine ...

Blood and urine metabolites were measured in two experiments for young (2-mo-old) and aged (20-mo-old) male Sprague-Dawley rats fed arginine-devoid diets made isonitrogenous to a control 1.12% arginine diet by adding alanine or glycine. Diet, fed for 7 or 13 d, had little effect on urinary or plasma ammonia and ...