Considerable attention has focused on regulation of central tryptophan hydroxylase (TPH) activity and protein expression. At the time of these earlier studies, it was thought that there was a single central TPH isoform. However, with the recent identification of TPH2, it becomes important to distinguish between regulatory effects on the protein expression and activity of the two isoforms. We have generated a TPH2-specific polyclonal antiserum (TPH2-6361) to study regulation of TPH2 at the protein level and to examine the distribution of TPH2 expression in rodent and human brain. TPH2 immunoreactivity (IR) was detected throughout the raphe nuclei, in lateral hypothalamic nuclei and in the pineal body of rodent and human brain. In addition, a prominent TPH2-IR fiber network was found in the human median eminence. We recently reported that glucocorticoid treatment of C57/Bl6 mice for 4 days markedly decreased TPH2 messenger RNA levels in the raphe nuclei, whereas TPH1 mRNA was unaffected. The glucocorticoid-elicited inhibition of TPH2 gene expression was blocked by co-administration of the glucocorticoid receptor antagonist mifepristone (RU-486). Using TPH2-6361, we have extended these findings to show a dose-dependent decrease in raphe TPH2 protein levels in response to 4 days of treatment with dexamethasone; this effect was blocked by co-administration of mifepristone. Moreover, the glucocorticoid-elicited inhibition of TPH2 was functionally significant: serotonin synthesis was significantly reduced in the frontal cortex of glucocorticoid-treated mice, an effect that was blocked by mifepristone coadministration. This study provides further evidence for the glucocorticoid regulation of serotonin biosynthesis via inhibition of TPH2 expression, and suggest that elevated glucocorticoid levels may be relevant to the etiology of psychiatric diseases, such as depression, where hypothalamic-pituitary-adrenal axis dysregulation has been documented.

The strength of the Ec.m. = 184 keV resonance in the 26gAl(p, gamma)27 reaction has been measured in inverse kinematics using the DRAGON recoil separator at TRIUMF's ISAC facility. We measure a value of omega gamma = 35 +/- 7 microeV and a resonance energy of Ec.m. = 184 +/- 1 keV, consistent with p-wave proton capture into the 7652(3) keV state in 27Si, and discuss the implications of these values for 26GAl nucleosynthesis in typical oxygen-neon white-dwarf novae.

A simple presence-absence (P-A) test was developed to provide a more economical and more sensitive method for conducting coliform analyses on municipal drinking water samples than the membrane filter (MF) technique. Over ninety percent of these samples routinely gave negative results by the M F method. A modified MacConkey broth, enriched to improve on acid and gas production by coliforms, was the isolation medium for the presumptive part of the P-A test.Parallel analyses of water samples were made by both the P-A and M F methods. Confirmatory tests established the reliability of the respective procedures to detect coliform bacteria. A statistical analysis of the results showed that the P-A test was more sensitive for detecting lower levels of pollution than the M F technique. Many of the confirmed positive P-A results came from P-A bottles that produced presumptive positive tests only after an extended incubation period of two to five days.The P-A test was about five times less expensive than the M F technique and by adding a few simple tests, the P-A procedure could give information on the presence of both fecal coliforrns and fecal streptococci. For several samples, fecal streptococci were found by P-A tests in the absence of detectable coliform bacteria by either the M F or P-A methods of analysis.

Intramuscular triglyceride (IMTG) accounts for only a fraction of the total lipid store in the human body. However, given its significant contribution as a substrate for ATP synthesis during exercise, and its proposed role in the development of skeletal muscle insulin resistance, IMTG metabolism has proved to be an area of great scientific interest over the last 20 years. Studies investigating IMTG utilisation during exercise remained equivocal, until methods using immunofluorescence microscopy enabled the muscle fibre type-specific assessment of IMTG content without the interference of extramyocellular adipocytes. Studies using this method convincingly demonstrated that in trained individuals 60-70% of IMTG can be depleted in type I muscle fibres during prolonged moderate-intensity exercise, and can account for up to 50% of total lipid oxidation (van Loon, 2004). Of more clinical relevance were studies highlighting the potential role of intramuscular lipid accumulation in the development of skeletal muscle insulin resistance. This hypothesis has been refined over the last decade, as highly insulin-sensitive, endurance-trained athletes exhibit higher levels of total IMTG and diacylglycerol (DAG) (Amati et al. 2011). It is now hypothesised that the accumulation of ceramides and certain species of membrane-bound DAG are responsible for the inhibition of insulin-mediated glucose uptake. The regulation of intramuscular lipolysis is an important area, given its role in the regulation of fatty acid supply to the mitochondria during exercise and in the determination of skeletal muscle lipid content and composition. However, the precise mechanisms regulating muscle lipolysis remain poorly understood. Hormone-sensitive lipase (HSL) was long considered to be the only enzyme involved in muscle lipolysis, until adipose triglyceride lipase (ATGL) was discovered and found to be expressed in skeletal muscle. As the activities of ATGL and HSL are highly specific for triglyceride (TG) and DAG, respectively, ATGL is now considered to contribute to the initial step in TG hydrolysis, with HSL primarily responsible for the breakdown of DAG.Important and intriguing new data have recently been presented by Alsted et al. (2013), which question the importance of HSL in contraction-mediated lipolysis in skeletal muscle. The authors hypothesised that lipases other than HSL are responsible for IMTG lipolysis during muscle contraction. In a well-designed series of experiments, the authors used a combination of pharmacological HSL inhibition (using a small-molecule inhibitor of HSL; 76-0079, Novo Nordisk, Bagsvaerd, Denmark) and HSL knockout (KO) mice, with an ex vivo electrical stimulation approach, to probe the effects of muscle contraction on IMTG lipolysis in the absence of HSL activity. In addition, they used histochemical methods to measure contraction-induced changes in IMTG content as a surrogate of IMTG lipolysis.First, the study demonstrated that IMTG content decreased following muscle contraction. This is in agreement with the fin...

The relationship between precursor supply and hepatic glucose output (HGO) was examined in 8 control subjects and 12 trauma patients after a fasting period of approximately 60 hours. Glucose kinetics were measured with a primed-constant infusion of [U-14C]glucose and [6-3H]glucose. The basal rate of HGO was 5.45 +/- 0.22 micromol x kg-1 x min-1 in the controls and 13.16 +/- 0.76 micromol x kg-1 x min-1 following trauma (p < 0.001). Four hours after amino acid infusion of 1.3 g x kg-1 x 24 h-1, HGO in the controls was unchanged at 5.35 +/- 0.22 micromol x kg-1 x min-1 but it had decreased to 11.71 +/- 0.67 micromol x kg-1 after trauma (p < 0.001). We conclude that increasing the supply of gluconeogenic precursors does not stimulate HGO in normal subjects after fasting or after severe trauma and that factors other than to availability of amino acids are responsible for the enhanced rate of HGO in trauma patients.