Search results for "compounds"
showing 10 items of 3372 documents
Effects of sulphonylureas on spontaneous motility and induced contractions in rat isolated uterus
1986
Abstract To clarify the action of sulphonylureas on calcium, the effect of tolbutamide and ghbenclamide has been investigated on a Ca-dependent process, the contractile activity of uterine smooth muscle. Both sulphonylureas antagonized the contractions evoked by CaCl2 in a non-competitive manner when the uterus was maintained in depolarizing solution and did not affect the spontaneous contractions of rat uterus. The capacity of tolbutamide and ghbenclamide to relax vanadate-induced contraction of rat uterus in Ca-free medium suggests that sulphonylureas may have an intracellular site of action related to cytosolic free Ca levels, or effect a reduction in Ca action.
Hormonal responsiveness in the Trier Social Stress Test and the dexamethasone‐corticotropin releasing hormone test in healthy individuals
2021
A number of different laboratory procedures investigate the hormonal response in a standardized pharmacological challenge test (dexamethasone-corticotropin releasing hormone; DEX-CRH) or in a psychosocial stress induction on the hypothalamic-pituitary-adrenocortical axis by the Trier Social Stress Test (TSST). However, the magnitude of the response related to the different stressors and the interaction of the responsiveness between the two tests is still unclear. Fifty-two participants underwent both the DEX-CRH test and the TSST on two separate days. The cortisol and the plasma adrenocorticotropic hormone (ACTH) release were assessed before and after the stress tests. For a specification o…
Transgenic overexpression of corticotropin releasing hormone provides partial protection against neurodegeneration in an in vivo model of acute excit…
2008
Abstract Corticotropin releasing hormone (CRH) is the central modulator of the mammalian hypothalamic–pituitary–adrenal (HPA) axis. In addition, CRH affects other processes in the brain including learning, memory, and synaptic plasticity. Moreover, CRH has been shown to play a role in nerve cell survival under apoptotic conditions and to serve as an endogenous neuroprotectant in vitro . Employing mice overexpressing murine CRH in the CNS, we observed a differential response of CRH-overexpressing mice (CRH-COE hom -Nes) to acute excitotoxic stress induced by kainate compared with controls (CRH-COE con -Nes). Interestingly, CRH-overexpression reduced the duration of epileptic seizures and pre…
Photo-DHEA--a functional photoreactive dehydroepiandrosterone (DHEA) analog.
2011
Abstract The steroid hormone dehydroepiandrosterone (DHEA) has beneficial effects on vascular function, survival of neurons, and fatty acid metabolism. However, a specific receptor for DHEA has not been identified to date. Here, we describe the synthesis of a photoreactive DHEA derivative (Photo-DHEA). In Photo-DHEA, typical characteristics of DHEA are conserved: (i) a “planar” tetracyclic ring system with a Δ 5 double bond, (ii) a 3β-hydroxyl group, and (iii) a keto group at C17. In cell-based assays, Photo-DHEA showed the same properties as DHEA. We conclude that Photo-DHEA is suitable for radioiodination to yield a tool for the identification of the elusive DHEA receptor.
Effects of dexamethasone on human synovial fibroblast-like cells, from osteoarthritic joints, in culture.
1990
The effect of Dexamethasone (DEX) on cell division and macromolecular synthesis was investigated in a line (McCoy cells, A 9) of synovial fibroblast-like cells derived from human osteoarthritic joints. DEX markedly reduced the proliferation of McCoy cells in a time and dose-dependent manner. The maximal inhibition (45%) was found at 500 nM DEX 24 h after incubation and was accompanied by the appearance of giant macrophage-like cells. After DEX treatment cells showed increased content of DNA, proteins and RNA together with the reduction of [3H]-thymidine incorporation into the TCA-precipitable fraction.
Respiratory Parameters after Systemic Corticotropin-Releasing Hormone Administration
1991
Neuroanatomical studies on the distribution of corticotropin-releasing hormone (CRH) and its receptors (7) as well as physiological data suggest a regulatory function of endogenous CRH in hypothalamic and extrahypothalamic brain areas [1, 4]. Endogenous CRH acts within the endocrine hypothalamo-pituitary-adrenal axis and affects cardiovascular regulation and respiration through extrahypothalamic pathways. CRH also stimulates gluconeogenesis and release of plasma-catecholamines. Our experiments in humans also demonstrate an influence on respiration and on heart rate activity after systemic application of CRH. Respiratory parameters and heart rate were analyzed during steady-state conditions …
Context dependent variation in corticosterone and phenotypic divergence of Rana arvalis populations along an acidification gradient
2022
Background Physiological processes, as immediate responses to the environment, are important mechanisms of phenotypic plasticity and can influence evolution at ecological time scales. In stressful environments, physiological stress responses of individuals are initiated and integrated via the release of hormones, such as corticosterone (CORT). In vertebrates, CORT influences energy metabolism and resource allocation to multiple fitness traits (e.g. growth and morphology) and can be an important mediator of rapid adaptation to environmental stress, such as acidification. The moor frog, Rana arvalis, shows adaptive divergence in larval life-histories and predator defense traits along an acidi…
Unexplored nucleophilic ring opening of aziridines.
2010
The reactivity of dianions of carboxylic acids towards aziridines has been studied. Although, a similar reactivity to that of enolates from ketones, esters or amides has been observed, the method directly yields g-aminoacids in one step. The method is complementary of previous results of enenediolate reactivity with other electrophiles. A comparative study with the reactivity of this enediolates with epoxides is included.
Partition of volatile compounds in pea globulin–maltodextrin aqueous two-phase system
2014
International audience; This study is based on the assumption that the off-flavour of pea proteins might be decreased using the retention of volatile compounds by a mixture with another biopolymer. The partition of volatile compounds in an aqueous system containing pea protein and maltodextrins was followed under thermodynamic incompatibility conditions. Firstly, the phase diagram of the system was established. Then, the partition of aroma compounds between the phase rich in protein and the phase rich in maltodextrin was measured by SPME–GC–MS. There was a transfer of volatile compounds during phase separation. Variations of pH were also used to vary the retention of volatile compounds by p…
Molecular docking and oxidation kinetics of 3-phenyl coumarin derivatives by human CYP2A13
2021
CYP2A13 enzyme is expressed in human extrahepatic tissues, while CYP2A6 is a hepatic enzyme. Reactions catalysed by CYP2A13 activate tobacco-specific nitrosamines and some other toxic xenobiotics in lungs.To compare oxidation characteristics and substrate-enzyme active site interactions in CYP2A13 vs CYP2A6, we evaluated CYP2A13 mediated oxidation characteristics of 23 coumarin derivatives and modelled their interactions at the enzyme active site.CYP2A13 did not oxidise six coumarin derivatives to corresponding fluorescent 7-hydroxycoumarins. The Km-values of the other coumarins varied 0.85���97 ��M, Vmax-values of the oxidation reaction varied 0.25���60 min���1, and intrinsic clearance var…