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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The binding of glucagon to the cell surface and the pathway of intracellular transport of the hormone in isolated mouse hepatocytes were studied by autoradiography, colloidal gold-labeled glucagon (Au-glucagon), and biochemical methods. In cells incubated with 1251-glucagon at 4 degrees C, the label was mainly localized to the plasma membrane even after 60 min of incubation. At 20 degrees C, the labeled ligand was internalized by the cells and the amount of internalized ligand increased with time of incubation. At 37 degrees C, the ligand was rapidly internalized and found to be associated with coated or uncoated vesicles. Au-glucagon experiments revealed clearly the process of internalization of glucagon. Au-glucagon bound to the plasma membrane was transported to coated regions and then internalized into vesicles via coated pits. Biochemical results supported these findings from autoradiography and Au-glucagon experiments. Thus, glucagon is internalized by hepatocytes via receptor-mediated endocytosis.
Anat Rec 1984 Dec
PMID:Receptor-mediated endocytosis of glucagon in isolated mouse hepatocytes. 609 92

Cells reactive to anti-anglerfish insulin, anti-porcine glucagon, anti-synthetic somatostatin, and anti-bovine pancreatic polypeptide were identified in adult Rana pipiens male pancreases using peroxidase anti-peroxidase immunohistochemistry. Insulin positive cells are columnar shaped and arranged in cords. Glucagon positive and somatostatin positive cells are located around the core of insulin positive cells. Isolated cells and clusters of cells of only one cell type are also found. Adjacent sections stained with anti-glucagon and anti-bovine pancreatic polypeptide showed that glucagon positivity and pancreatic polypeptide positivity are found in the same cells. Comparison of double stained adjacent sections confirmed the presence of these two antigens in the same cells, and further showed the occasional presence of cells which are positive to only glucagon or pancreatic polypeptide. Staining of rat pancreas with these two antisera showed that glucagon and pancreatic polypeptide are present in two distinct cell populations. Morphometric quantitation of immunohistochemically stained sections of Rana pipiens pancreases showed that about 2% of the pancreas is endocrine tissue. Of this, 43% is comprised of insulin positive cells, and 43% is occupied by glucagon-pancreatic polypeptide positive cells. Somatostatin positive cell occupy about 14% of the total islet volume. The presence of glucagon and pancreatic polypeptide in the same cell population in the frog, but in different cell populations in mammals, may reflect special functional adaptation in this species, or a close relation of these two hormones and their cells of production during evolution.
Anat Rec 1980 Feb
PMID:Distribution and morphometric quantitation of pancreatic endocrine cell types in the frog, Rana pipiens. 610 38

The electron microscopic localization of insulin, glucagon, somatostatin, and pancreatic polypeptide (PP) in the pancreas of the iguanid lizard, Anolis carolinensis was studied by the unlabeled antibody peroxidase-antiperoxidase immunocytochemical technique. Insulin, glucagon, and somatostatin were localized absolutely to those cells previously identified on the basis of the characteristics of their secretory granules as being beta cells, alpha cells, and D cells, respectively. The secretory granule cores of the PP-containing cells appeared to be ellipsoidal with a semi-major axis of 450 nm and a semi-minor axis of 365 nm. This previously unidentified cell type is named the F cell, in keeping with the localization of PP to the original F cell of the canine pancreas. Without immunocytochemical staining, the qualitative ultrastructural characteristics of the F cell secretory granules were inadequate to permit identification of the F cell, especially with regard to the D cell.
Anat Rec 1981 Jan
PMID:Four hormones in the pancreas of the lizard, Anolis carolinensis. 611 34

Insulin, glucagon, somatostatin, and pancreatic polypeptide (PP) were localized in the pancreas of the common garter snake, Thamnophis sirtalis, by light and transmission electron microscopic (TEM) immunocytochemistry. Colloidal gold-protein A was used for TEM localization and the peroxidase--antiperoxidase complex technique was used for light microscopy. The glucagon-containing A cells and the insulin-positive B cells were the most numerous cell types. The somatostatin-containing D cells made up about 15% of the endocrine cells. PP-positive F cells were a minor cell type. The only topographic arrangement of the cells within the endocrine-rich areas that was apparent was the peripheral localization of the D and F cells. Cells of a specific cell type were sometimes grouped together. At the electron microscopic (EM) level, the gold particles (indicating the presence of hormone) were localized nearly exclusively over the secretory granules of the reactive cells. The alpha-granules were the largest found and were predominantly electron dense with a moderately electron-dense periphery. PP-containing granules were the smallest. The somatostatin-reactive delta-granules were round and moderately electron opaque. The beta-granules were heterogeneous in appearance. The morphognomy of the secretory granules of the major endocrine cell types is qualitatively similar to that of mammals. Whether or not the quantitative and/or associative differences contribute to the marked metabolic differences between reptiles and mammals, remains to be determined.
Anat Rec 1984 Feb
PMID:Immunocytochemical localization of four hormones in the pancreas of the garter snake, Thamnophis sirtalis. 614 66

Cell types containing insulin, glucagon, somatostatin, and pancreatic polypeptide were identified in guinea pig islets with light and electron microscopic immunoperoxidase staining. Cells containing immunostainable insulin (B cells) are located throughout the islets, including the islet periphery, and contain irregularly shaped granules (350-550 nm). Granule contents are of variable opacity and are often fragmented but not crystalloid. Cells containing immunoreactive glucagon (A cells) are found in the interior of islets and contain numerous spheroid electron-opaque granules (250-350 nm). Cells containing immunoreactive somatostatin (D cells) have elongate, axonlike processes that end adjacent to islet capillaries. D cells, which are very numerous and distributed uniformly throughout the islet parenchyma, contain small spheroid granules (150-25 nm) of pale electron opacity. Cells with immunoreactive pancreatic polypeptide (F cells) are rare in islets but numerous among the exocrine parenchyma. F cells contain pale spheroid granules (100-200 nm). Morphological criteria are reliable indicators for A cells and B cells, but D cells and F cells require immunostaining for positive identification.
Anat Rec 1984 Apr
PMID:Immunocytochemical identification of cells containing insulin, glucagon, somatostatin, and pancreatic polypeptide in the islets of Langerhans of the guinea pig pancreas with light and electron microscopy. 614 72

The cellular localization and regional distribution of insulin- and glucagonlike substance, C-peptide-like immunoreactivity, thiol:protein disulphide oxidoreductase, TPO (E.C.1.8.4.2.), and insulin/glucagon-specific proteinase, ISP (E.C.3.4.22.-), are studied in the CNS of man, adult and juvenile rats, mice, tortoises, and frogs by use of immunohistochemistry. Furthermore, the content of immunoreactive insulin, glucagon, and C-peptide was estimated in human cadaver brains by radioimmunoassay. It could be shown that insulinlike immunoreactive material is widely distributed in the human brain and the CNS of juvenile rats as well as in mice, whereas in the CNS of adult rats and nonmammalian animals (frogs, tortoises) the polypeptide is restricted to a few nerve cell populations. C-peptide immunoreactivity was demonstrated in human CNS in the same nerve cells as insulin. By use of two different glucagon-antisera it was revealed that gut-type glucagon occurs in many nerve cells of human and mouse brains, as well as in the CNS of juvenile rats. On the other hand, pancreas-type glucagon was less widely distributed in the human brain and nearly not detectable in the CNS of mice and rats. With the exception of neurosecretory nerve cells, there was a high degree of coincidence between the localization of insulin and TPO. The immunoreaction against the ISP antiserum was weak, but correlated well with the distribution of insulin-immunoreactivity. The occurrence of TPO and ISP in the brain demonstrates the ability of nervous tissue to degrade insulin and glucagon. By radioimmunoassay it was established that human brain contains insulin, glucagon and C-peptide at concentrations that exceed blood levels. We conclude from our data that, at least in part, cerebral insulin and glucagon are products of the brain itself.
Anat Rec 1983 Sep
PMID:Insulin- and glucagonlike peptides in the brain. 635 89

The endocrine pancreas of the channel catfish is segregated into a large primary islet and numerous smaller secondary islets. In view of cell distribution differences in mammalian islets of ventral and dorsal primordia, we have determined the percentage volumes of insulin-, glucagon-, and somatostatin-containing cells in primary and secondary catfish islets to ascertain if these islets correlated with those derived from ventral and dorsal primordia in mammals. Islets were immunocytochemically stained using antisera to anglerfish insulin, porcine glucagon, and synthetic somatostatin and volume densities were quantified on light micrographs by point-counting procedures. In both primary and secondary islets the insulin-, glucagon-, and somatostatin-containing cells comprised approximately 32%, 23%, and 38% of the endocrine cell volumes, respectively. Therefore, the cell populations did not reflect any embryological differences between the two groups of islets. In this study, the volume densities of insulin-reactive cells in the primary islet were less than previously reported, and the overall insulin staining was about one-half of that seen in mammals. The volume density of somatostatin-reactive cells in primary islets was greater than previously reported. Based on these data, primary and secondary islets of the catfish do not appear to have a similar development to the ventral and dorsal islets of the mammalian system.
Anat Rec 1984 Jul
PMID:An immunocytochemical study of the pancreatic islet system of the channel catfish. 638 Mar 40

Blood samples were taken before and after a cross country race over the marathon distance of 42 km. There was a rise in blood glucose and plasma free fatty acids and glycerol associated with a rise in plasma cortisol and glucagon but the fall in insulin was not significant (P > 0.05). Plasma potassium and albumin concentrations increased, calcium decreased and there was no change in sodium or bicarbonate concentrations. There was an increase in plasma urea, creatinine, uric acid, bilirubin and isocitrate dehydrogenase but no change in alkaline phosphatase. There was a rise in plasma creatine kinase. These results of a competitive race are compared with those of the 80 km non-competitive Golden Horseshoe Ride.
Vet Rec 1980 Dec 06
PMID:A biochemical study of the Arab Horse Society's marathon race. 746 99

Two dogs with metabolic epidermal necrosis had hyperkeratosis of the footpads accompanied by erythematous, erosive and crusting lesions affecting the muzzle, external genitalia, perineum and periocular regions. Histopathological examination of skin biopsies revealed a superficial hydropic dermatitis with marked parakeratosis. Both dogs had high plasma activities of alkaline phosphatase and alanine aminotransferase and high concentrations of glucose, and also a marked hypoaminoacidaemia. Despite these similarities, the cutaneous eruptions were associated with different underlying diseases. One dog had a pancreatic carcinoma which had metastasised widely; the primary tumour and the metastases showed glucagon immunoreactivity on immunocytochemical staining, and the dog's plasma glucagon concentration was markedly greater than that of control dogs. The other dog had diffuse hepatic disease; its plasma glucagon concentration was similar to that of control samples and cirrhosis was identified post mortem. Metabolic epidermal necrosis in dogs is a distinct cutaneous reaction pattern which may be associated with different underlying systemic diseases; however, the pathogenesis of the skin lesions remains unclear.
Vet Rec 1995 May 06
PMID:Metabolic epidermal necrosis in two dogs with different underlying diseases. 763 36

Recently it has been observed that a subpopulation of gut endocrine cells in vertebrates express Trk-like proteins, suggesting that neurotrophins could regulate the synthesis and storage of amines and peptides of these cells. Nevertheless, the peptides and amines present in the endocrine cells that express Trks have not been characterized. In this study we used immunohistochemistry to investigate the occurrence of Trk-like proteins (TrkA-like, TrkB-like and TrkC-like) and the possible co-localization of these with peptides and/or biogenic amines in the endocrine cells of the stomach of three teleost (bass, gilt-head and scorpionfish). No TrkA-like immunoreactivity (IR) was detected in the stomach of these species, whereas TrkB-like IR and TrkC-like IR were observed in numerous cells of the gastric epithelium. TrkB-like immunoreactive cells were present in all three species examined, and were particularly abundant in the blind sac. Conversely, TrkC-like immunoreactive cells were found only in the bass stomach, apparently co-localized with TrkB-like IR. TrkB-like IR was found co-localized with somatostatin IR in scorpionfish, and with somatostatin and CGRP IR in gilt-head and bass. Gastric endocrine cells expressing 5-HT, glucagon, insulin, met-, leu-enkephalin, substance P, PYY, VIP, CCK, NPY, bombesin and motilin were unreactive for Trk-like proteins. The present results provide direct evidence for the occurrence of Trk-like neurotrophin receptor proteins in a subpopulation of the teleostean gastric endocrine cells and suggest that neurotrophins could regulate, as in neurons, the expression of some neuropeptides such as somatostatin and CGRP.
Anat Rec 1999 11 01
PMID:Co-localization of Trk neurotrophin receptors and regulatory peptides in the endocrine cells of the teleostean stomach. 1052 80


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