Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mucosal population of small intestine of rats was exposed in vivo to various concentrations of vinblastine sulfate for 30 and 60 min and the activities of glycyl-L-valine and glycyl-L-leucine hydrolase were measured in the treated mucosa of the upper jejunal segment. A significant depression in the activity of these dipeptidases was observed which was further found to be dose dependent.
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PMID:A study of intestinal dipeptidases of rats: effect of in vivo mucosal exposure to vinblastine. 16 May 71

Kinetics of the transport systems common for entry of L-isoleucine, L-leucine, and L-valine in Salmonella typhimurium LT2 have been analyzed as a function of substrateconcentration in the range of 0.5 to 45 muM. The systems of transport mutants, KA203 (ilvT3) and KA204 (ilvT4), are composed of two components; apparent Km values for uptake of isoleucine, leucine, and valine by the low Km component are 2 muM, 2 to 3 muM, and 1 muM, respectively, and by the high Km component 30 muM, 20 to 40 muM, and 0.1 mM, respectively. The transport system(s) of the wild type has not been separated into components but rather displays single Km values of 9 muM for isoleucine, 10 muM for leucine, and 30 muM for valine. The transport activity of the wild type was repressed by L-leucine, alpha ketoisocaproate, glycyl-L-isoleucine, glycyl-L-leucine, and glycyl-L-methionine. That for the transport mutants was repressed by L-alanine, L-isoleucine, L-methionine, L-valine, alpha-ketoisovalerate, alpha-keto-beta-methylvalerate, glycyl-L-alanine, glycyl-L-threonine, and glycyl-L-valine, in addition to the compounds described above. Repression of the mutant transport systems resulted in disappearance of the low Km component for valine uptake, together with a decrease in Vmax of the high Km component; the kinetic analysis with isoleucine and leucine as substrates was not possible because of poor uptake. The maximum reduction of the transport activity for isoleucine was obtained after growing cells for two to three generations in a medium supplemented with repressor, and for the depression, protein synthesis was essential after removal of the repressor. The transport activity for labeled isoleucine in the transport mutant and wild-type strains was inhibited by unlabeled L-alanine, L-cysteine, L-isoleucine, L-leucine, L-methionine, L-threonine, and L-valine. D-Amino acids neither repressed nor inhibited the transport activity of cells for entry of isoleucine.
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PMID:Repression and inhibition of transport systems for branched-chain amino acids in Salmonella typhimurium. 32 Jan 86

Activities of L-glycyl-L-valine and L-glycyl-L-leucine dipeptidase were studied in the mucosa of the small intestine of rats following intraperitoneal administration of vinblastine sulfate (1.0 mg/kg). Activities of these dipeptidases were depressed significantly; the effect was maximal between 4 and 5 h after the injection and lasted for more than 16 h. The depression in the enzyme activities reached even up to 95% when the alkaloid was administered repeatedly in 4-hourly intervals. The present results, showing a dose-dependent inhibitory effect on these dipeptidases, suggest a toxic effect on the enzymes in addition to simple inhibition resulting from a blockade of cell division. The former possibility was examined by incubating mucosal homogenates with various concentrations of the alkaloid for 30 min. Subsequent measurement of the activities showed a significant depression when the alkaloid concentration was raised to 10 microgram/mg wet mucosa. It is concluded that vinblastine sulfate not only arrests the mitosis of the crypts but influences, additionally, the enzymatic complements of the enterocytes.
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PMID:A study of small intestinal dipeptidases of rats: effect of vinblastine treatment. 48 47

Growth rate, plasma amino acid, and alpha-keto acid concentrations and activities of the branched-chain amino acid degradative enzymes of rats were measured. Effects of ingestion of excessive amounts of branched-chain amino acids on these variables were determined. Excessive intake of a single branched-chain amino acid led rapidly to elevated plasma concentration of both the amino acid administered and its corresponding alpha-keto acid and, if the rats had previously been fed a low protein diet, to an increase in liver branched-chain alpha-keto acid dehydrogenase activity. Only leucine caused, in addition, marked growth and food intake depression and decreased plasma isoleucine, valine, alpha-keto-beta-methylvaleric acid and alpha-keto isovaleric acid concentrations. The growth depression was associated food intake depression and could be moderated by addition of isoleucine and valine to the diet. The decreases in plasma isoleucine, valine, alpha-keto-beta-methylvaleric acid and alpha-keto isovaleric acid were not caused by increased degradation of these metabolites to carbon dioxide as branched-chain amino acid oxidation rates in vivo were unchanged by leucine loading and the degradative enzymes were unchanged in adequately fed rats. The decreased concentrations of these amino and keto acids may be the result of decreased protein degradation or increased protein synthesis, possibly mediated by insulin.
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PMID:Effects of branched-chain amino acid antagonism in the rat on tissue amino acid and keto acid concentrations. 87 Jun 54

In four experiments, the interactions of leucine, isoleucine and valine in turkey poults were studied. The additon of 1.50% excess leucine to a 22% protein starter diet, marginal in isoleucine and valine, depressed growth. This growth depression was corrected by the addition of valine and isoleucine. The addition of the excess leucine caused a decrease in plasma valine and isileucine concentrations in experiments 3 and 4, and plasma valine concentration in experiment 1. The addition of valine caused a marked linear increase in plasma valine with little or no effect on plasma isoleucine. The addition of isoleucine to the diet caused an increase in plasma isoleucine. Plasma valine, however, was decreased by the addition of isoleucine to a high-leucine diet. It is concluded that interactions exist in turkey poults between leucine-valine, leucine-isoleucine and isoleucine-valine and that the growth reduction caused by added leucine can be partly alleviated by addition of valine or by valine plus isoleucine, but not be isoleucine alone.
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PMID:Leucine, isoleucine and valine interactions in turkey poults. 99 1

Plasma albumin levels were measured in partially hepatectomized, sham operated and control rats. The levels fell in both the partially hepatectomized and sham operated groups; while the latter group returned to normal within a few days, the low plasma albumin in the partially hepatectomized animals was sustained. Albumin synthesis rates in the isolated perfused rat liver were measured in the three groups of animals at varying intervals after partial hepatectomy. There was a significant depression of albumin synthesis rate in terms of both liver and whole animal weights when compared to the sham operated and control animals. This depression was almost completely reversed by the addition of arginine, asparagine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan and valine added together to 10 times their normal plasma concentrations. The addition of hydrocortisone had no effect on the albumin synthesis rate after partial hepatectomy. Studies in vivo in the three groups of animals (partially hepatectomized, sham operated and control animals) revealed a fall in the albumin catabolic rate after partial hepatectomy coinciding with the fall in the albumin synthesis rate. An hypothesis whereby the amino acids may have their stimulatory effect is proposed.
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PMID:Albumin synthesis and catabolism following partial hepatectomy in the rat. The effects of amino acids and adrenocortical steroids on albumin synthesis after partial hepatectomy. 115 98

The possible role of amino acid availability and a functional hypothalamic-pituitary-adrenal axis in the mood disturbances often reported in postpartum women and in users of the oral contraceptive was examined by measuring amino acids and doing a dexamethasone suppression test. Plasma cortisol, tryptophan, tyrosine, their competing amino acids in brain uptake (CAA), and the effect of 1mg dexamethasone were determined in 10 women taking oral contraceptives, 31 women 3 days postpartum, and 9 controls. The pill contained 30 mcg ethinyl estradiol and .075 mg gestodene (2 women), and 30 mg ethinyl estradiol and .15 mg desogestrel (8 women). The subject also took self-rating mood scales: Zung Depression, Zung Anxiety, Beck Depression and State Anxiety Inventory. Cortisol was significantly higher in postpartum women and pill users than in normal controls. Tryptophan, valine, isoleucine and leucine were lower in postpartum women. Tyrosine and tyrosine CAA were lower in postpartum women and pill users. 80% of the postpartum group had negative dexamethasone suppression tests, i.e., cortisol 5 mcg/dl 24 hours after 1 mg dexamethasone. After dexamethasone valine was significantly higher and tryptophan/CAA and tyrosine/CAA ratios were lower, as a result of slightly lower tryptophan and tyrosine and slightly higher CAAs. Furthermore, effects on the amino acid ratios were only evident in women exhibiting dexamethasone suppression. There was a significant negative correlation between depression and anxiety scores and the tryptophan/CAA ratio. The results indicated first that the dexamethasone suppression test is an invalid marker for major depression, and also that availability of the amino acid precursors of brain neurotransmitters may affect mood in the puerperium.
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PMID:Disturbances in dexamethasone suppression test and lower availability of L-tryptophan and tyrosine in early puerperium and in women under contraceptive therapy. 156 Apr 30

Some children with coeliac disease show behavioural disorders such as depression and other signs which have been correlated with reduced central monoamine metabolism. We have therefore investigated the brain availability of the monoamine precursors tryptophan and tyrosine in 15 untreated children with coeliac disease and 12 treated children with coeliac disease as well as in 12 control children. Significantly decreased plasma concentrations of tryptophan were found in untreated children (mean (SD) 13 (4) mumols/l, p less than 0.001) compared with treated children (31 (13) mumols/l), and in both groups of coeliac children when compared with control children (81 (22) mumols/l). A significantly lower ratio of plasma tryptophan to large neutral amino acids (tyrosine, valine, isoleucine, leucine, and phenylalanine) was also observed, which could indicate impaired brain availability of tryptophan in coeliac children and was more pronounced in untreated children. The impaired availability of tryptophan could produce decreased central serotonin synthesis and in turn behaviour disorders in children with coeliac disease.
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PMID:Plasma precursor amino acids of central nervous system monoamines in children with coeliac disease. 177 52

Sixty patients with chronic renal failure (CRF) were studied for the rates of lipid peroxidation (LPO), the state of the antioxidative system (AOS) as well as for the morphofunctional state of biomembranes in renal tubules measured by excretion of low-molecular compounds tested in urine x by means of proton nuclear magnetic resonance spectroscopy. The control group numbered 35 patients with glomerulonephritis free of functional disturbances in the kidneys. The increased values of malonic dialdehyde levels in red blood cells and blood serum and those of diene conjugates in red blood cell membranes provide evidence for a significant increase of the LPO levels. Furthermore, depression of the AOS was revealed, manifested by the decreased levels of blood serum alpha-tocopherol as well as by unstable levels of superoxide dismutase in red blood cells. In the presence of the high LPO levels significant tubular dysfunctions were progressing, parallel with aggravation of renal function. Disturbances detected in excretion and reabsorption of amino acids (leucine, alanine, glycine, valine, histidine), thin organic acids and ketone bodies in CRF patients point to the existence of disturbances in tubular membranes. Tubular dysfunction appears to be caused by the disturbances of the biomembrane morphofunctional states induced by the high levels of free radical oxidation as well as by the AOS function failure.
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PMID:[Free radical oxidation and tubular dysfunctions in patients with chronic kidney failure]. 194 50

The deleterious effects of branched-chain amino acid (BCAA) antagonism caused by excess dietary leucine include growth depression and subnormal valine and isoleucine pools. To investigate mechanisms causing these changes, rats were gavage-fed low-protein (9%) diets with or without BCAA supplements, and the metabolism of another BCAA (valine) was measured in incubated rat epitrochlearis muscles. A 10% leucine supplement (HL-10) inhibited growth; growth remained subnormal even when 2.6% isoleucine and 2.4% valine (HLIV-10) were added to the diet. Valine decarboxylation in muscle increased 170-270% in rats fed the HL-10 or HLIV-10 diets, but was still markedly lower than we previously found in muscle of rats fed a 14% protein diet. Valine incorporation into muscle protein as an estimate of protein synthesis was unaffected by any of the BCAA supplements. When a lower (4%) concentration of leucine (without or with 0.16% isoleucine and 0.16% valine) was studied, growth was also suppressed but only if rats had not been preconditioned to 9% protein. Although increased BCAA decarboxylation in muscle caused by excess dietary leucine contributes to low valine and isoleucine pools, abnormal growth appears to be independent of low valine and isoleucine levels and is not reflected in suppression of valine incorporation into muscle protein.
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PMID:Leucine-induced amino acid antagonism in rats: muscle valine metabolism and growth impairment. 200 1


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