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Release Increases (release + increase)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Adipocyte prolactin: regulation of release and putative functions

DIABETES OBESITY & METABOLISM, Issue 4 2007
T. Brandebourg
Pituitary-derived prolactin (PRL) is a well-known regulator of the lactating mammary gland. However, the recent discovery that human adipose tissue produces PRL as well as expresses the PRL receptor (PRLR) highlights a previously unappreciated action of PRL as a cytokine involved in adipose tissue function. Biologically active PRL is secreted by all adipose tissue depots examined: breast, visceral and subcutaneous. The expression of adipose PRL is regulated by a non-pituitary, alternative superdistal promoter. PRL expression and release increases during early pre-adipocyte differentiation and is stimulated by cyclic AMP activators, including , adrenergic receptor agonists. PRL release from subcutaneous adipose explants is attenuated during obesity, suggesting that adipose PRL production is altered by the metabolic state. Several lines of evidence indicate that PRL suppresses lipid storage as well as the release of adipokines such as adiponectin, interleukin-6 and possibly leptin. PRL has also been implicated in the regulation of adipogenesis. A newly developed PRL-secreting human adipocyte cell line, LS14, should allow comprehensive examination of the regulation and function of adipocyte-derived PRL. Collectively, these studies raise the prospect that PRL affects energy homeostasis through its action as an adipokine and is involved in the manifestation of insulin resistance. [source]

Voltammetric Investigation of Zinc Release from Metallothioneins Modulated by the Glutathione Redox Couple and Separated with a Porous Membrane

ELECTROANALYSIS, Issue 20 2008
Lin Liu
Abstract Glutathione (GSH), in addition to serving as a redox buffer in cellular environment, has been suggested as a modulator in metal regulation and homeostasis by metallothioneins (MTs). The interactions of MTs with both GSH and its oxidized form GSSG have been shown to govern the direction of metal transfer. Common methods for the determination of zinc release from MTs modulated by GSH/GSSG either involve radioactive species or enzymes or are labor-intensive. In this study, upon separation of Zn2+ from the reaction mixture of MTs and GSH with a centrifugal filter membrane, differential pulse voltammetry (DPV) was used for the Zn2+ quantification. The same approach is extended to the studies of metal transfer between Zn7MT with a GSH/GSSG mixture and that between Zn7MT with GSSG. The concomitant conversion between the free thiol and disulfide bonds was confirmed with UV-vis spectrophotometry. The results demonstrate that GSSG, GSH, and the GSH/GSSG mixture all modulate zinc release from Zn7MT. The percentage of zinc release increases in the order of GSH, GSSG, and the GSH/GSSG mixture. The new approach is demonstrated to be well suited for investigation of redox regulation of MT and its reaction with zinc-containing enzymes. [source]

The effects of methylene blue on ovine post-pneumonectomy pulmonary oedema

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2010
E. V. SUBOROV
Background: We recently reported that post-pneumonectomy pulmonary oedema (PPO) occurs after ventilating the remaining lung with excessive tidal volumes. Studies in small animals have indicated that nitric oxide (NO) release increases in hyper-inflated lungs, but confirmatory evidence from larger animals is still lacking. We hypothesized that PPO could be prevented by methylene blue (MB), an inhibitor of NO synthase. Methods: Sheep were subjected to a right-sided pneumonectomy (PE) and randomly assigned to a protectively ventilated group ((PROTV group, n=7) with tidal volumes of 6 ml/kg at 20 inflations/min and a positive end-expiratory pressure (PEEP) of 2 cmH2O, and two groups undergoing ,injurious ventilation' (INJV) with tidal volumes of 12 ml/kg and zero end-expiratory pressure (ZEEP), a control group (INJV group, n=7) and a treatment group subjected to MB 1 h after PE (INJV+MB group, n=7). Haemodynamic variables, lung mechanics, blood gases and plasma nitrites and nitrates (NOx) were determined. Results: PE reduced pulmonary blood volume, extravascular lung water (EVLWI) and quasistatic lung compliance in all groups, in parallel with a rise in peak airway pressure (P<0.05). In the INJV group, pulmonary arterial pressure, EVLWI and pulmonary vascular permeability index increased and arterial oxygenation decreased towards cessation of the experiments. These changes were not antagonized by MB. Plasma NOx increased in all the groups compared with baseline, but with no intergroup difference. Conclusion: MB did not reduce PPO and accumulation of NOx in sheep subjected to ventilation with excessive tidal volumes and ZEEP. [source]

The Hypothalamic Insulin-Like Growth Factor-1 Receptor and Its Relationship to Gonadotropin-Releasing Hormones Neurones During Postnatal Development

JOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2004
S. S. Daftary
Abstract Reproduction in vertebrates is controlled by hypophysiotropic gonadotropin-releasing hormone (GnRH) neurones. Pulsatile GnRH release increases during reproductive development, resulting in the onset and progression of puberty and, ultimately, the acquisition and maintenance of adult reproductive function. These changes in GnRH release are largely due to inputs to GnRH cells from other factors, including the neurotrophic factor, insulin-like growth factor-1 (IGF-1). Here, molecular studies were undertaken to quantify expression of IGF-1 receptor (IGF-1R) mRNA in the preoptic area-anterior hypothalamus (POA-AH) and mediobasal hypothalamus (MBH)-median eminence (ME), the sites of GnRH perikarya and neuroterminals, respectively. Immunocytochemical studies were also carried out to study the anatomical relationship between the IGF-1R and GnRH neurones. Experiments were performed in a developmental context using neonatal (P5), peripubertal (,P30) and adult (P60) male and female mice. We found that IGF-1R mRNA levels in the POA-AH were significantly different among all age groups, with levels higher at P60 then P5 or ,P30. Levels of IGF-1R mRNA in the MBH-ME were lower at P5 than ,P30 or P60. Qualitative observations suggested that IGF-1R immunoreactivity in POA-AH increased from P5 through P60. Quantitative double-label immunocytochemistry studies showed that GnRH perikarya expressed IGF-1R. Taken together, the results demonstrate expression of, and developmental changes in, IGF-1R gene and protein in brain regions containing GnRH and other neuroendocrine cells. Moreover, the novel finding that the IGF-1R is expressed on GnRH perikarya in vivo suggests a potential direct anatomical locus where IGF-1 can regulate reproductive development and function. [source]