Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polypeptide material displaying glucagon-like immunoreactivity was isolated from porcine colon using immunoaffinity chromatography. The immunoreactive material was tightly bound to high molecular weight proteins but was dissociated by 0.1% w/v sodium dodecyl sulphate solution into immunoreactive components of approximate molecular weights 12,000,8000,5000 and 3000. These components reacted at least 50 times more strongly with antibodies specific for the N-terminal region of glucagon than with antibodies specific for the C-terminal region of glucagon. While the 8000 and 3000 dalton fractions were homogeneous, the 12,000 and 5000 dalton fractions were resolved into multiple bands by isoelectric focusing. The 12,000 dalton fraction was devoid of glycogenolytic and lipolytic activity, was not insulin releasing and showed no ability to bind to receptor sites specific for glucagon on hepatic plasma membranes and to active hepatic adenylate cyclase. The 8000 and 5000 dalton components showed weak lipolytic activity. The possible significance of colonic glucagon-like immunoreactivity relative to pancreatic glucagon and immunoreactivity from other tissues is discussed.
 ...
PMID:Physicochemical and biological properties of glucagon-like polypeptides from porcine colon. 45 44

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

Acute insulin resistance developed after scald injury in the mouse. After 2h plasma glucose and insulin concentrations were each raised about two-fold. Glucose metabolism was studied in vitro in soleus muscles isolated at this time. Glycolysis and glycogen synthesis, and their stimulation by insulin, were unchanged in muscles from scalded mice, and insulin-stimulated transport of 2-deoxyglucose slightly increased, showing that the insulin resistance seen in vivo is not maintained in isolated tissues. Binding of insulin to liver cell membranes prepared from scalded mice was unaltered, whilst that of glucagon was slightly but significantly reduced, showing that changes in polypeptide-hormone receptors can occur within this short time. It was concluded that the acute loss of sensitivity to insulin after injury does not result from a change in insulin receptor sites and presumably reflects an impairment of glucose metabolism in vivo mediated by circulating hormones.
 ...
PMID:Studies on the mechanism of insulin resistance after injury in the mouse. 64 63

A radioimmunoassay for the measurement of gastric inhibitory polypeptide (GIP) in unextracted plasma in man has been developed using a rabbit antiserum raised against porcine GIP. Porcine GIP was employed also as standard and to produce a 125I-labelled tracer. The assay was able to distinguish 110 pg/ml GIP from zero in plasma samples. Negligible cross-reactivity was demonstrated with cholecystokinin, insulin, pancreatic polypeptide, glucagon, secretin, and vasoactive intestinal polypeptide. The mean overnight fasting plasma GIP level in 28 normal subjects was 203 pg/ml (range: undetectable--420 pg/ml). Plasma GIP levels rose, within 45 minutes of eating a mixed meal, to a mean level of 1573 pg/ml.
 ...
PMID:Radioimmunoassay of gastric inhibitory polypeptide. 67 95

We studied the secretion of insulin, glucagon, and the exocrine secretion of the isolated perfused porcine pancreas in response to vasoactive intestinal polypeptide (VIP) in concentrations ranging from 30 to 18,750 pmol/liter at various concentrations of glucose in the perfusion medium. VIP stimulated the insulin and glucagon secretion in a dose-dependent manner. The response pattern was critically dependent on the glucose concentration. In the presence of a glucose concentration of 7.5 mmol/liter, VIP enhanced insulin release without affecting glucagon release. Maximal insulin release was obtained at a VIP concentration of 3,750 pmol/liter. At a glucose concentration of 5.0 or 3.5 mmol/liter, VIP enhanced glucagon release but not insulin release. VIP stimulated the exocrine secretion in a secretin-like manner. The lowest concentration of VIP observed to increase pancreatic exocrine secretion was 30 pmol/liter, whereas the maximal pancreatic exocrine responses were not obtained.
 ...
PMID:Secretory effects of VIP on isolated perfused porcine pancreas. 69 59

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

Synthetic vasoactive intestinal polypeptide (VIP) was infused at a dose of 50 ng/kg/min for 10 min into the cranial pancreaticoduodenal artery in anesthetized dogs. Both mean blood flow and plasma glucagon concentration in the cranial pancreaticoduodenal vein were significantly enhanced during the infusion, indicating a great augmentation in glucagon output. The pancreatic venous plasma concentration of insulin was not significantly raised, but its output increased during the infusion, again due to the increase in plasma flow. Plasma concentration of glucagon in the femoral artery was not significantly augmented, whereas that of insulin was enhanced during VIP infusion. Mean arterial plasma glucose levels rose gradually during the infusion. Intrapancreatic pretreatment with propranolol failed to exert any significant inhibiting effect upon the VIP-induced enhancement in plasma glucose, pancreatic venous blood flow, or bihormonal output. These results suggest that the vasoactive polypeptide of intestinal origin may regulate the function of the endocrine pancreas and that this effect may not be mediated mainly via the beta-adrenergic receptor system.
 ...
PMID:Effect of vasoactive intestinal polypeptide infused intrapancreatically on glucagon and insulin secretion. 86 85

Polypeptide antigen, glucagon, antibodies to glucagon and non-immune globulins were immobilised on agarose using CNBr and a bifunctional oxirane. Irrespective of the ligand immolilised, positively charged groups introduced to conjugates by CNBr caused electrostatic interactions with impurities and soluble biospecific ligands. Solvents required for elution of bound antibodies and antigens were more strongly deforming when immunoaffinity conjugates were prepared with CNBr than with the oxirane. This is attributed to compound affinity resulting from reinforcement of biospecific by non-biospecific interactions. Strongly deforming solvents were still required for oxirane conjugates, however, when antibodies had high affinity for antigen.
 ...
PMID:Comparison of non-biospecific effects in immunoaffinity chromatography using cyanogen bromide and bifunctional oxirane as immobilising agents. 87 26


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