Disease relevance of Glu-gly-lys-arg-pro-trp-ile-leu

• Highly purified rat gastric immunoreactive xenopsin displayed xenopsin-like biologic effects, producing hypotension in the anesthetized rat and contracting the isolated guinea pig ileum [1].
• Xenopsin- and neurotensin-like peptides in gastric juice from patients with duodenal ulcers [2].
• Administration of 10 microgram of xenopsin per kg of body weight brought about a hyperglycemic response and rapid and sharp elevations of the hormones in the pancreatic vein [3].
• These findings suggest that cerulein, in the dose and intervals applied, initiated hyperplasia and induced hypertrophy of the pancreas, whereas xenopsin only initiated hyperplasia [4].

Psychiatry related information on Glu-gly-lys-arg-pro-trp-ile-leu

• Therefore, we examined the effect of xenin, a recently identified xenopsin-related pentacosa peptide, on feeding behavior of fasted rats [5].
• The effects of intracerebral microinjections of neurotensin and xenopsin on self-stimulation of the medial prefrontal cortex of the rat were studied [6].
• Furthermore, amphetamine-induced locomotor activity was not blocked by NT or xenopsin [7].

High impact information on Glu-gly-lys-arg-pro-trp-ile-leu

• Evidence for the presence of xenopsin-related peptide(s) in the gastric mucosa of mammals [8].
• Determination of the amino acid sequence revealed a 25-amino acid peptide having 6 C-terminal amino acids in common with amphibian xenopsin [9].
• Preliminary assignments of these components were made by comparing these experimental molecular weights to those predicted for regions within the xenopsin, caerulein, thyrotropin-releasing hormone, and PGLa precursors [10].
• The HPLC chromatograms showed the secretion to be a complex mixture with over 30 components at similar levels to the four peptides previously isolated from X. laevis skin, i.e. xenopsin, caerulein, thyrotropin-releasing hormone, and PGLa [10].
• These findings suggest that there may be a renin/angiotensin-like system for the generation of xenopsin-related peptides in the stomach [1].

Biological context of Glu-gly-lys-arg-pro-trp-ile-leu

• The rank order of potency (IC50 in nM) was XP (0.1) greater than NT (0.9) approximately avian XP (1.0) greater than NM-N (1.6), which could not be explained on the basis of differential peptide degradation [11].
• Tachyphylaxis and cross-tachyphylaxis were observed after repeated NT and XP addition to muscle strips [11].
• We investigated the effects of the neurotensin analogue xenopsin on regional blood flow, central hemodynamics, and stimulated acid secretion in awake conscious dogs [12].

Anatomical context of Glu-gly-lys-arg-pro-trp-ile-leu

• Biologically active xenopsin-related peptide(s) were shown by radioimmunoassay to be liberated in nearly micromolar concentrations from substrate(s) with Mr greater than 70,000 during acid extraction of mammalian and avian stomach [1].
• The effects of xenin 25, a peptide of the neurotensin/xenopsin family, were examined on the motility of the guinea pig jejunum and colon in vitro [13].
• Possible conformations involved in the binding of neurotensin, xenopsin and bradykinin molecules to mast cell receptors [14].
• Xenin is a 25-amino acid peptide of the neurotensin/xenopsin family identified in gastric mucosa as well as in a number of tissues, including the pancreas of various mammals [15].
• Peptides related to the amphibian octapeptide xenopsin are present in various locations in mammalians, such as the gastrointestinal mucosa or brain tissue [5].

Associations of Glu-gly-lys-arg-pro-trp-ile-leu with other chemical compounds

• 3. Among the tested neurotensin analogues, neurotensin 8-13, neuromedin-N, and xenopsin also increased [Ca2+]i, whereas neurotensin 1-11 and neurotensin 1-8 did not elicit detectable responses [16].
• Gel permeation chromatography of skin-derived xenopsin immunoreactivity identified a single molecular species larger than synthetic xenopsin which was resolved into two components by reverse-phase HPLC with retention times similar to synthetic xenopsin and kinetensin [17].
• LANT-6, xenopsin and neuromedin N stimulate cyclic GMP at neurotensin receptors [18].
• Gel chromatography on Sephadex G-25 was used in order to characterize the immunoreactive material; both XPLI and NTLI eluted in a single peak at the position of synthetic xenopsin and neurotensin [19].
• Analysis by gel permeation chromatography and high performance liquid chromatography demonstrated that both the neurotensin- and xenopsin-like immunoreactivity was heterogeneous and an increase in molecular complexity on pentagastrin-stimulation was observed [2].

Gene context of Glu-gly-lys-arg-pro-trp-ile-leu

• In mesenteric segments, NT and its homologs increased Isc with the order of potency: NT greater than NM-N greater than xenopsin [20].
• Neurotensin, Lys8-Asn9-neurotensin(8-13) and xenopsin were efficiently hydrolysed while neuromedin N and kinetensin underwent little if any proteolysis by the peptidase [21].
• The order of potency was neurotensin-(8-13) greater than neurotensin greater than xenopsin greater than neuromedin N greater than LANT-6 [18].
• The order of affinity of the peptides for the neurotensin receptor was neurotensin-(8-13) greater than xenopsin greater than neurotensin greater than neuromedin N greater than LANT-6 [18].
• It is concluded that gastric antral G-cells in addition to gastrin also contain the amphibian peptide xenopsin [22].

Analytical, diagnostic and therapeutic context of Glu-gly-lys-arg-pro-trp-ile-leu

• Using immunohistochemistry and radioimmunoassay, substance(s) related to the amphibian octapeptide xenopsin (XP) were demonstrated in the gastric mucosa of humans and dogs [8].
• The eluates were monitored with a radioimmunoassay for amphibian xenopsin [9].
• As immunohistochemistry has also indicated the presence of xenopsin immunoreactivity in man, we extracted in the present investigation xenopsin-immunoreactive material from human gastric mucosa and purified it to homogeneity with several high performance liquid chromatography (HPLC) reverse phase and ion exchange chromatographic steps [9].
• No significant differences in the release of xenopsin- or neurotensin-like immunoreactive were observed between patients with selective proximal vagotomy and patients without operation [2].
• When subjected to HPLC on mu-Bondapak C-18, the xenopsin-related peptides generated by the lysate eluted near to those formed by cathepsin D and when tested in a radioreceptor assay for neurotensin, they displayed similar cross-reactivities (peak 2, approximately 50%; peak 1, approximately 100%) [23].

References