Search results for "Transferase"
showing 10 items of 1030 documents
Fos-related antigen 2 (Fra-2) memorizes photoperiod in the rat pineal gland
2004
As the physiological role of fos-related antigen-2 (Fra-2) is largely unknown and since the pineal plays an important role in the photoperiodic control of the body, we have tested the hypothesis that Fra-2 expression is photoperiod-dependent and may be involved in imprinting photoperiod on the pineal gland and the body as a whole. To this end, we have investigated Fra-2 mRNA expression and Fra-2 protein expression under various light/dark (LD) cycles. A clear nocturnal increase occurs for both monitored parameters under all photoperiodic conditions studied. The level of Fra-2 protein expression clearly depends on photoperiod, because the amount of protein at dark onset and during the night …
The role of arginine-vasopressin for pineal melatonin synthesis in the rat: involvement of vasopressinergic receptors.
1991
Abstract The endogenously synthesized nonapeptide arginine vasopressin (AVP) is thought to be involved in transduction of photic information to the pineal gland. The enhancement of circulating AVP leads to a suppression of the nocturnal melatonin surge the mechanisms of which are unknown so far. We therefore studied the effect of dDAVP, an AVP analog with antidiuretic but without vasopressor activity, on pineal melatonin synthesis in Sprague-Dawley and AVP-deficient Brattleboro rats. The nocturnal intra-arterial application of dDAVP mimicked the inhibitory effect of AVP on the activity of the rate-limiting enzyme for pineal melatonin synthesis, N-acetyltransferase (NAT), in both rat strains…
Homoarginine Levels are Regulated by L-Arginine: Glycine Amidinotransferase and Affect Stroke Outcome: Results from Human and Murine Studies
2013
Background— Endogenous arginine homologues, including homoarginine, have been identified as novel biomarkers for cardiovascular disease and outcomes. Our studies of human cohorts and a confirmatory murine model associated the arginine homologue homoarginine and its metabolism with stroke pathology and outcome. Methods and Results— Increasing homoarginine levels were independently associated with a reduction in all-cause mortality in patients with ischemic stroke (7.4 years of follow-up; hazard ratio for 1-SD homoarginine, 0.79 [95% confidence interval, 0.64–0.96]; P =0.019; n=389). Homoarginine was also independently associated with the National Institutes of Health Stroke Scale+age score …
Interrelationship between demethylation of p-nitroanisole and conjugation of p-nitrophenol in rat liver
1973
The metabolism of p-nitroanisole (pNA) and p-nitrophenol (pNP) was studied in isolated rat livers perfused with a hemoglobin-free medium. The activity and viability of the surviving organ was tested by recording pH, “arterial” and “venous” oxygen tension as well as the disappearance of added pNP. pNA is converted to its primary metabolite pNP which, in turn, is excreted into the perfusion medium as conjugates. The coordination of pNA oxidation and the conjugation reactions of pNP were investigated. When 50 μM pNA is added as substrate 0.4±0.1 nmoles×ml−1×(g liver)−1 are excreted as pNP-glucuronide and 3.5±0.2 nmoles×ml−1×(g liver)−1 as the sulphate within 90 min. When pNP itself (50 μM) is …
Blood Glutathione as an Index of Radiation-Induced Oxidative Stress in Mice and Humans
1997
Abstract The effect of x-rays on GSH and GSSG levels in blood was studied in mice and humans. An HPLC method that we recently developed was applied to accurately determine GSSG levels in blood. The glutathione redox status (GSH/GSSG) decreases after irradiation. This effect is mainly due to an increase in GSSG levels. Mice received single fraction radiotherapy, at total doses of 1.0 to 7.0 Gy. Changes in GSSG in mouse blood can be detected 10 min after irradiation and last for 6 h within a range of 2.0–7.0 Gy. The highest levels of GSSG (20.1 ± 2.9 μ M), a 4.7-fold increase as compared with controls) in mouse blood are found 2 h after radiation exposure (5 Gy). Breast and lung cancer patien…
Liver-specific methionine adenosyltransferase MAT1A gene expression is associated with a specific pattern of promoter methylation and histone acetyla…
2000
Methionine adenosyltransferase (MAT) is the enzyme that catalyzes the synthesis of S-adenosylmethionine (AdoMet), the main donor of methyl groups in the cell. In mammals MAT is the product of two genes, MAT1A and MAT2A. MAT1A is expressed only in the mature liver whereas fetal hepatocytes, extrahepatic tissues and liver cancer cells express MAT2A. The mechanisms behind the tissue and differentiation state specific MAT1A expression are not known. In the present work we examined MAT1A promoter methylation status by means of methylation sensitive restriction enzyme analysis. Our data indicate that MAT1A promoter is hypomethylated in liver and hypermethylated in kidney and fetal rat hepatocytes…
Phosphodiesterase 10A in the Rat Pineal Gland: Localization, Daily and Seasonal Regulation of Expression and Influence on Signal Transduction
2010
The cyclic nucleotide phosphodiesterase 10A (PDE10A) is highly expressed in striatal spiny projection neurons and represents a therapeutic target for the treatment of psychotic symptoms. As reported previously [J Biol Chem 2009; 284:7606–7622], in this study PDE10A was seen to be additionally expressed in the pineal gland where the levels of PDE10A transcript display daily changes. As with the transcript, the amount of PDE10A protein was found to be under daily and seasonal regulation. The observed cyclicity in the amount of PDE10A mRNA persists under constant darkness, is blocked by constant light and is modulated by the lighting regime. It therefore appears to be driven by the master cloc…
Low Homoarginine Levels in the Prognosis of Patients With Acute Chest Pain.
2016
Background The endogenous amino acid homoarginine predicts mortality in cerebro‐ and cardiovascular disease. The objective was to explore whether homoarginine is associated with atrial fibrillation ( AF ) and outcome in patients with acute chest pain. Methods and Results One thousand six hundred forty‐nine patients with acute chest pain were consecutively enrolled in this study, of whom 589 were diagnosed acute coronary syndrome ( ACS ). On admission, plasma concentrations of homoarginine as well as brain natriuretic peptide ( BNP ), and high‐sensitivity assayed troponin I (hsTnI) were determined along with electrocardiography ( ECG ) variables. During a median follow‐up of 183 days, 60 ma…
Behavioural parameters in aged rats are related to LTP and gene expression of ChAT and NMDA-NR2 subunits in the striatum.
2004
Striatal parameters were assessed for their relevance to age-related behavioural decline. Forty aged rats (28-30 months) were tested in the water maze and open field. Of these, seven superior and seven inferior learners were compared with each other in terms of levels of in vitro short- and long-term potentiation (STP and LTP), and gene expression of choline acetyltransferase (ChAT) as well as of the NMDA-NR2A-C subunits assessed by quantitative RT-PCR. Results revealed that the superior as compared with the inferior learners had higher levels of ChAT mRNA in the striatum. For the superior group, ChAT mRNA was correlated with escape on to the cued platform in the water maze, whereas level o…
Percutaneous antegrade electropapillotomy. Study in dogs.
1984
Antegrade electropapillotomy using the percutaneous transcystic approach was successfully performed in 11 of 16 dogs. When the intervention was effective, the pressure gradient between common bile duct and duodenum decreased from 6 to 1.3 mm Hg on average and returned to gradients slightly below the initial values after 4 weeks, owing to reactivation of the sphincter mechanism. Ineffective cutting, however, resulted in a temporary pressure rise. In one dog a papillary stenosis developed and was relieved by antegrade electrocutting. Irrespective of the success of the papillotomy, rises in levels of serum glutamine oxaloacetic and pyruvic transaminase, alkaline phosphatase, serum amylase and …