Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polypeptides with somatostatin-like immunoreactivity (SLI) and approximate molecular weights of 12,000, 3,000, and 1,600 were isolated from acid extracts of the canine extrahypothalamic brain and stomach by affinity chromatography, ion exchange, gel filtration, and isoelectric focusing. The 12,000-dalton SLI was acidic, whereas the 3,000- and 1,600-dalton forms were basic molecules. All SLI fractions diluted proportionally in a RIA employing an antibody directed toward the central region of somatostatin. Like synthetic somatostatin, the 1,600-dalton SLI inhibited pentagastrin-stimulated gastric acid secretion in rats. Neither of the two larger forms of SLI were dissociated by 6 M guanidinium HCl. However, treatment with dithiothreitol, which reduces disulfide bonds, resulted in the conversion of a large portion of the 12,000-dalton SLI to the 1,600-dalton form. These data are compatible with a model of a 12,000-dalton SLI consisting of somatostatin bound to an acidic polypeptide by a peptide bond and a disulfide bond. Variations in the relative rates of hydrolysis of the peptide bonds and reduction of the disulfide bonds in different tissues may result in three forms of the 12,000-dalton polypeptide in which both bonds are intact or one of the two bonds is cleaved.
 ...
PMID:Properties of somatostatin-like immunoreactive polypeptides in the canine extrahypothalamic brain and stomach. 49 81

Several gastrointestinal peptides with proven or suggested endocrine or paracrine functions influence gastric acid secretion, gastrointestinal motility, and mucosal blood flow. Increased or decreased release of such factors could participate in the pathogenesis of duodenal ulcer disease by inducing increased gastric acid concentration in the duodenal bulb. To date, increased stimulation of parietal cells by gastrin has been demonstrated only in patients with gastrinoma, G-cell hyperplasia, gastric outlet obstruction, hyperparathyroidism, excluded antrum, and short bowel syndrome, but not in the usual duodenal ulcer disease. Also, a defective inhibition of parietal cell function by endocrine or paracrine factors, such as gastric inhibitory polypeptide, secretin, somatostatin and vasoactive intestinal polypeptide, seems not to exist in patients with duodenal ulcer disease. However, as long as the physiology of gastrointestinal peptides in gastric secretion and motility is not understood, a possible role of these factors in the pathogenesis of simple duodenal ulcer disease cannot be excluded.
 ...
PMID:Endocrinology of duodenal ulcer. 51 78

The role of nerves that liberate vasoactive intestinal polypeptide (VIP) in the porcine pancrease as mediators of the atropine-resistant action of the vagus on flow and bicarbonate (HCO3) secretion was examined. Efferent electrical stimulation of the vagus in atropinized pigs produced a profuse flow of pancreatic juice with high HCO3 content concomitantly with a significant increase in pancreatic VIP output from 13 to 113 fmol/min. Intravenous administration of somatostatin (SRIF) during continuous electrical vagal stimulation caused a parallel suppression of the VIP release and the pancreatic fluid and HCO3 secretion to prestimulatory values. The SRIF-induced reduction in fluid and HCO3 secretion seemed to be mediated via an inhibition of the VIP release rather than through a direct effect on the exocrine cells, inasmuch as SRIF did not influence the VIP-provoked exocrine response from the in vitro isolated perfused porcine pancreas. The results support the view that VIP is transmitter in the vagally induced atropine-resistant water and HCO3 secretion from the porcine pancreas.
 ...
PMID:Vasoactive intestinal polypeptide in vagally mediated pancreatic secretion of fluid and HCO3. 51 50

In 9 fetuses, 9 to 24 weeks-old, the occurrence and relative distribution of argentaffin cells, as well as of cells immunoreactive to somatostatin (SRIF), glucagon-like polypeptide (GLI), pancreatic polypeptide (PP) and substance P (SP) were studied in five segments of the colon (appendix, cecum, ascending colon, descending colon, and rectosigmoid). For each colonic segment, data concerned with the occurrence of endocrine cells were expressed either as mean absolute numbers of specific cells per entire mucosal section, or as cell densities per mm3 of mucosa after calculation of the mucosal volume of the sections. Argentaffin, GLI, SRIF and PP immunoreactive cells are all present in relatively large numbers, scattered along the entire length of the colonic mucosa as early as the 9th-10th week of gestation, whereas substance P-containing cells occur sporadically and first appear during the 4th-17th week. Until the 20th week, with progressing embryonic development, an increase was determined in absolute numbers per section of all types of endocrine cells in all segments of the colon. This observation is clearly related to the general growth of the colonic mucosa, since cell densities per mm3 of mucosa do not greatly change or even decrease during gestation. However, it is possible that densities of argentaffin, GLI and BPP cells increase in the appendix around the 14th-17th week of gestation. Between 20th and 24th weeks, absolute numbers of cells per section remain stable or slightly increase, while cell densities tend rather to decrease in all segments. These data demonstrate that some endocrine cells are present very early in the human fetal colon, but their functional significance remains to be elucidated.
 ...
PMID:Ontogeny and distribution of certain oendocrine cells in the human fetal large intestine. Histochemical and immunocytochemical studies. 51 32

A reliable, sensitive, reproducible and specific radioimmunoassay for cholecystokinin-pancreozymin (CCK) has been developed, using rabbit antisera to highly purified porcine hormone. The natural occurring variant of CCK (39-CCK), in which the ordinary CCK is lengthened from its N-terminus by a hexapeptide, labelled with 125J, and repurified by column chromatography on Sephadex G-10 and on SP-Sephadex C-25, was used as tracer. Separation from antibody-bound labelled 39-CCK was carried out using a double antibody procedure. Non-specific interference with the assay system was abolished by ethanol extractions. Highly purified porcine CCK was used as standard. No significant crossreaction was found with gastrin, motilin, vasoactive polypeptide (VIP), gastric inhibitory polypeptide (GIP), natural and synthetic secretin, pancreatic glucagon or insulin. The sensitivity of the assay is approximately 40 pg/ml of test solution. The mean immunoreactive CCK concentration in 45 fasting normal subjects was 222 pg/ml increasing after food ingestion to 480 pg/ml. Somatostatin was able to abolish the stimulated CCK release. Elevated CCK concentrations were found in chronic pancreatitis. Immunohistochemical identification of pancreozymin cells was carried out either in surgical samples or in biopsy material. Approximately 1650 CCK cells per cross-section in the duodenum of humans have been found. The CCK cells usually appeared elongated, oval or pyramidal in shape and were observed to reach the lumen with their apical cell pole.
 ...
PMID:Estimation of cholecystokinin-pancreozymin (CCK) in human plasma and tissue by a specific radioimmunoassay and the immunohistochemical identification of pancreozymin-producing cells in the duodenum of humans. 56 41

In dogs with chronic duodenal and gastric fistula the effect of somatostatin (SST) on the endogenous release of secretin and pancretic polypeptide (PP) was investigated. The release of secretin following intraduodenal acid administration was significantly reduced by SST. While PP increased significantly after a test meal, its release was completely suppressed by SST.
 ...
PMID:[Effect of somatostatin on the endogenous release of secretin and pancreatic polypeptide in the dog]. 67 2

A radioimmunoassay capable of detecting 300 fg somatostatin has been developed and levels of the polypeptide in gastrointestinal tissues from man, dog, and rat have been measured. Rapid freezing of collected samples and careful control of extraction is necessary. Concentrations in different regions of dog antrum (425 +/- 50 to 773 +/- 254 ng/g tissue) are similar to those in antrum from duodenal ulcer patients and control subjects: 614 +/- 125 and 465 +/- 104 ng/g tissue respectively. Levels in histologically normal human pancreas (253 +/- 43 ng/g tissue) are comparable with those in dog pancreas (333 +/- 66 ng/g tissue), whereas in two cases of neonatal hypoglycaemia the concentration exceeded 3000 ng/g tissue. On gel chromatography the majority of immunoreactive somatostatin elutes as the synthetic tetradecapeptide and a small fraction as a larger species.
 ...
PMID:Gastrointestinal somatostatin: extraction and radioimmunoassay in different species. 68 May 97

Somatostatin-like immunoreactivity (SLI) in the peripheral venous plasma of dogs and in their pancreatic and gastric venous effluents was characterized and compared with synthetic somatostatin. Both endogenuous plasma SLI and somatostatin added to plasma were eluted from Sephadex gels at pH 8.8 in the 150,000--200,000-mol wt region but at pH 2.5 both appeared in the 1,500--2,000-mol wt region. The SLI released from the isolated dog pancreas perfused with plasma-free buffer was eluted entirely as a 1,600-dalton polypeptide, but when the pancreas was perfused with plasma, SLI was eluted in the 150,000--200,000-mol wt zone. Affinity chromatography of plasma samples on immobilized antibodies directed against the central portion of the somatostatin molecule (residues 5--9 and 11) removed approximately equal to 90% of both endogenous SLI and somatostatin added to plasma, but neither was removed by affinity chromatography on antibodies directed against the NH2-terminal region of somatostatin (residues 1--4). The SLI from plasma and from pancreas perfusate isolated by affinity chromatography was identical in molecular size, charge, and immunometric properties to synthetic somatostatin. It is concluded that endogenous SLI is secreted by the pancreas and stomach in a form not distinguishable from synthetic somatostatin, but circulates in plasma bound to large molecular weight components; the NH2-terminal residues of somatostatin appear to be important in this binding.
 ...
PMID:Properties of endogenous somatostatin-like immunoreactivity and synthetic somatostatin in dog plasma. 74 73

It is now well established that insulin biosynthesis proceeds through a precursor molecule, proinsulin. This single polypeptide chain form has been identified as a ribosomal product in the microsomal fraction from islet tissues. The newly synthesized peptide chain, after folding and thiol oxidation, is transferred to the Golgi apparatus where it begins to undergo proteolytic processing to insulin and packaging into secretory granules. The secretion from the cells of significant amounts of newly synthesized material by exocytosis begins only one hour or more after biosynthesis and this process is regulated by several factors, including glucose. Foci of current attention discussed in this paper include (1) the possible existence of larger precursor forms than proinsulin, especially short-lived biosynthetic transients with extended NH2-termini analogous to the recently described immunoglobulin L chain and proparathyroid hormone precursors; (2) the large-scale production of insulin by chemical or genetic engineering approaches; (3) isolation of beta-cell plasma membranes; (4) regulatory mechanisms for the biosynthesis and secretion of insulin, the possible role of mRNA modification in this process, and effects of somatostatin on insulin biosynthesis and secretion; (5) studies on the secretion, metabolism and clinical usefulness of the proinsulin C-peptide; (6) finally, the biosynthesis of glucagon and other peptide hormones and the general significance of precursor forms.
 ...
PMID:Biosynthesis of insulin and glucagon: a view of the current state of the art. 78 79

In addition to established gastrointestinal hormones--secretin, cholecystokinin-pancreozymin (CCK-PZ), gastrin, and glucagon---some 30 polypeptides with gastrointestinal actions can be listed. New aspects of these substances include the following: Gastrin and vasoactive intestinal peptide (VIP) can be also encountered in the central nervous system and may act as transmitters. CCK-PZ-serum concentrations are found markedly elevated in patients with exocrine pancreatic insufficiency; this may provide the opportunity to establish a realtively simple screening test. Moreover, there is evidence that serum-CCK-PZ levels serve as satiety signal. Secretin secretion is said to be enhanced in hunger and then to act as a lipolytic hormone. In addition to enteroglucagon, a gastrintestinal peptide identical to pancreatic glucagon has been detected. Gastric inhibitory polypeptide (GIP) inhibits gastric secretion and motility (enterogastrone activity) and together with glucose it stimulates insulin release (incretin activity). Motilin increases lower esophageal sphincter pressure, enhances gastric pepsin secretion and slows down gastric evacuation. Serum levels of pancreatic polypeptide may be found elevated as a diagnostic index in patients with endocrine peptide tumors of the pancreas. Recently, the potential importance of local (paracrine) actions of gastrointestinal polypeptides has been amphasized. Predominantly paracrine activity is exhibited by some prototype hormones, e.g. somatostatin, substance P, bombesian, and the non-polypeptide compounds, prostaglandins.
 ...
PMID:[New views on gastrointestinal hormones]. 85 99


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>