Search results for "Endocrine System"
showing 10 items of 1530 documents
Peripheral motor action of glucagon-like peptide-1 through enteric neuronal receptors
2010
Background Glucagon-like peptide-1 (GLP-1) is a proglucagon-derived peptide expressed in the enteroendocrine-L cells of small and large intestine and released in response to meal ingestion. Glucagon-like peptide-1 exerts inhibitory effects on gastrointestinal motility through vagal afferents and central nervous mechanisms; however, no data is available about a direct influence on the gastrointestinal wall. Our aim was to investigate the effects of GLP-1 on the spontaneous and evoked mechanical activity of mouse duodenum and colon and to identify the presence and distribution of GLP-1 receptors (GLP-1R) in the muscle coat. Methods Organ bath recording technique and immunohistochemistry wer…
The Effects of Microelectrophoretically Applied Melatonin, Putative Transmitters, Thyroxine and Sex Hormones on the Electrical Activity of Pineal Cel…
1981
ABSTRACT The effects of microelectrophoretic application of melatonin, noradrenaline, acetylcholine, thyroxine, testosterone and oestrone on pineal cell electrical activity were evaluated. With the exception of acetylcholine and oestrone pineal cells showed a circadian rhythm in sensitivity to the application of the substances. It is apparent from these studies, that (1) transmitters and hormones can bring about direct changes in the firing frequency of pineal cells, (2) all pineal cells do not respond to these substances in the same way and (3) that melatonin either produced in the pineal organ or reaching the gland via the general circulation may be capable of directly influencing the cel…
Expression and regulation of mPer1 in immortalized GnRH neurons.
2003
Hypothalamic GnRH (gonadotropin-releasing hormone) neurons play a critical role in the initiation and maintenance of reproduction competence. Using the mouse GnRH neuronal cell line, GT1-7, we have characterized the expression of the gene mPer1, a recognized key element of the mammalian circadian clockwork. Both mPer1 transcripts and the 136 kDa mPER1 gene product could be detected in these cells. Immunocytochemical analysis also confirmed expression of mPER1 both in vitro and in vivo in GnRH neurons. Activation of cyclic AMP signalling pathways in vitro elevated GnRH secretion as well as mPer1 expression and nuclear mPER1 immunoreactivity. As mPER1 is known to feedback on transcriptional a…
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.
MR-Tomographie bei Hodenprozessen
1992
The value of T1-weighted sequences after intravenous administration of Gd-DTPA and of T2-weighted sequences was compared in 43 patients suspected of having scrotal abnormalities. T2-weighted sequences gave better demonstration of the tunica albuginea and better contrast between tumor and parenchyma. The two techniques were equally sensitive for demonstrating testicular tumors but orchitis was better demonstrated on the contrast enhanced sequences. Motion artifacts were less marked in the T1-weighted sequences with contrast enhancement. In selected cases, contrast enhancement may be a valuable addition to native protocols. Our experience has indicated that MRI provides specific findings in c…
Glucose lowering and anti-atherogenic effects of incretin-based therapies: GLP-1 analogues and DPP-4-inhibitors
2009
Type 2 diabetes is a chronic, progressive disease with a multi-faceted pathophysiology. Beyond the known defects of insulin resistance and beta-cell insufficiency, derangement of incretin hormones normally produced from the gut wall in response to food intake play an important role. In recent years, the 'incretin-based' therapies (IBTs) have been developed to address hyperglycemia through either mimicking the action of the endogenous incretin glucagon-like polypeptide (GLP-1) (GLP-1 receptor agonists) or by inhibiting the activity of the enzyme that degrades GLP-1 (the dipeptyl peptidase-4 inhibitors).We reviewed available evidence on the glucose lowering and anti-atherogenic effects of IBT…
In vitro synthesis of dopamine and noradrenaline in the isolated rat pineal gland: day-night variations and effects of electrical stimulation.
1989
: Isolated rat pineal glands were incubated in vitro in a medium containing [I4C]dopamine or [14C]tyrosine, and the tissue contents of l4C-labelled and total dopamine and noradrenaline were determined by HPLC followed by electrochemical detection and scintillation spectrometry. During incubation with [l4C]dopamine, the labelled amine accumulated in pineal glands and was partially converted into [l4C]noradrenaline. Nomifensine, a neuronal amine uptake blocker, largely inhibited the accumulation of [l4C]dopamine and the formation of [14C]noradrenaline. These experiments demonstrated dopamine β-hydroxylase activity in the sympathetic nerves of the pineal gland. During incubation with [14C]tyro…
GLP-2 receptor expression in excitatory and inhibitory enteric neurons and its role in mouse duodenum contractility
2011
Background Glucagon-like peptide 2 (GLP-2), a nutrient-responsive hormone, exerts various actions in the gastrointestinal tract that are mediated by a G-protein coupled receptor called GLP-2R. A little information is available on GLP-2R expression in enteric neurons and nothing on the interstitial cells of Cajal (ICC). Methods We investigated presence and distribution of the GLP-2R in the mouse duodenum by immunohistochemistry and the potential motor effects of GLP-2 on the spontaneous and neurally evoked mechanical activity. Key Results The GLP-2R was expressed by the myenteric and submucosal neurons. Labelling was also present in nerve varicosities within the circular muscular layer an…
'TRPing' synaptic ribbon function in the rat pineal gland: neuroendocrine regulation involves the capsaicin receptor TRPV1.
2009
Synaptic ribbons (SRs) are presynaptic structures thought to regulate and facilitate multivesicular release. In the pineal gland, they display a circadian rhythm with higher levels at night paralleling melatonin synthesis. To gain more insight into the processes involved and the possible functions of these structures, a series of experiments were conducted in rodents. We studied the regional distribution of a molecular marker of pineal SRs, the kinesin motor KIF3A in the gland. Respective immunoreactivity was abundant in central regions of the gland where sympathetic fibers were less dense, and vice versa, revealing that intercellular communication between adjacent pinealocytes is enhanced …
Comparative Effectiveness of DPP-4 Inhibitors Versus Sulfonylurea for the Treatment of Type 2 Diabetes in Routine Clinical Practice: A Retrospective …
2018
Introduction DPP-4 inhibitors (DPP4i) and sulfonylureas are popular second-line therapies for type 2 diabetes (T2D), but there is a paucity of real-world studies comparing their effectiveness in routine clinical practice. Methods This was a multicenter retrospective study on diabetes outpatient clinics comparing the effectiveness of DPP4i versus gliclazide extended release. The primary endpoint was change from baseline in HbA1c. Secondary endpoints were changes in fasting plasma glucose, body weight, and systolic blood pressure. Automated software extracted data from the same clinical electronic chart system at all centers. Propensity score matching (PSM) was used to generate comparable coh…