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

The present study was initiated to determine whether specific hormones would influence adenylate cyclase activity within the maxillary-palatal complex during formation of the hamster secondary palate. Stages from initial appearance of the palatal processes to shortly after birth were studied. Highest basal adenylate cyclase activities occurred during the earliest periods of palate development. This basal enzyme activity began to diminish as palatal fusion occurred and remained lowered until birth. Activation of adenylate cyclase by fluoride was maximal at concentrations of 5-10 mM, and was observed throughout the span of palatal development. Fluoride activation of adenylate cyclase was greatest prior to fusion of the palatal processes, then decreased until birth when a slightly increased enzymatic stimulation was seen. Norepinephrine and epinphrine were the catecholamines most capable of inducing increased activation of adenylate cyclase at most periods of palatal growth. Increased enzyme activity in the presence of norepinephrine was more susceptible to antagonism by the beta adrenergic agent, propranolol, than to the alpha adrenergic agent, phentolamine. The remaining catecholamines, namely isoproterenol and dopamine, displayed a lesser ability to activate the enzyme, and adenylate cyclase was not equally responsive to these catecholamines at identical developmental stages. Other hormones, i.e. histamine, serotonin, thyrotropin, growth hormone, thyroxine and glucagon were generally ineffective in activating the enzyme. Phosphodiesterase activity was not detected until shortly before birth.
Anat Rec 1976 Jun
PMID:Catecholamine-sensitive adenylate cyclase in the developing golden hamster palate. 17 49

Six types of endocrine cells showing immunolabelling against gut or pancreatic islet hormones were identified in the pancreatic-bile duct system of the normal adult rat at the light and electron microscopic levels. They were located within the epithelial lining of the duct system from the intercalated portion to its duodenal opening. However, the distribution and frequency of each endocrine cell varied along the length of the duct system. While insulin, glucagon, somatostatin, and pancreatic polypeptide cells were widely distributed along the entire duct system, small numbers of cholecystokinin and serotonin cells were confined to the terminal portion. A considerable number of somatostatin cells were concentrated in gland-like pouches of the terminal portion of the common pancreatic-bile duct. When the accessory pancreatic duct was present, insulin, glucagon, and somatostatin cells were also found in its epithelial lining. Electron microscopically, the specific content of the secretory granules of all endocrine cells was confirmed by immunolabelling or cytochemical staining. Further the characteristics of the secretory granules of each endocrine cell type corresponded to those present in the same kind of endocrine cells in gut or pancreatic islet. The duct endocrine cells displayed a particular ultrastructural appearance. The "open type cells" were highly polarized, with their apical cytoplasmic process reaching the duct lumen, whereas "closed type cells" showed long basal cytoplasmic processes with no connection with the duct lumen. In general, insulin, and somatostatin cells were of the "open type", while no morphological connection with the duct lumen was found for glucagon and pancreatic polypeptide cells. The presence of various duct endocrine cells with their particular ultrastructural appearance implies that they may take part in modulating the function of the duct system.
Anat Rec 1992 Feb
PMID:Characterization of the endocrine cells in the pancreatic-bile duct system of the rat. 134 74

Sections of pancreatic islets from C57BL/6J mice aged 3, 14, and 24 months, consisting of islets derived from the dorsal primordium (DPI) and from the ventral primordium (VPI), were immunostained using the peroxidase-antiperoxidase (PAP) procedure for localization of glucagon (A cells) and somatostatin (D cells). The density (A or D cell area/islet area) of immunopositive cells were determined using computer-assisted image analysis. The density of A cells was significantly less in VPI of 14- and 24-month-old mice compared to 3-month-old mice. The density of A cells in 24 month DPI was less than 3 month DPI but no different from 14 month DPI. The mean area (microns 2) of A cells (only in DPI) was significantly less at 24 months compared to the 3 and 14 month groups. There were no differences in somatostatin staining when comparing the three age groups, although at all ages the density of D cells was always greater in the DPI. In conclusion, the major difference between the young and older mice was a deficiency of glucagon-stained cells in older mice. These results might be important in explaining improved glucose tolerance in aged C57BL/6J mice.
Anat Rec 1990 Sep
PMID:Age-related immunohistochemical studies of A and D cells in pancreatic islets of C57BL/6J mice. 197 9

Ultrastructural and autoradiographic observations of cultured chick hepatocytes under the following conditions are described: Induction of glycogen synthesis with glucose alone and glucose plus insulin, and glucagon-induced glycogen breakdown. Profiles of hepatocytes cultured in medium containing 10 mM glucose showed typical cellular organelles and occasionally a few glycogen granules. After incubation of hepatocytes with 3H-glucose, silver grains were found over these sparse glycogen granules, indicating a low level of glycogen synthesis by a few cells. After addition of 75 mM glucose for 1 hr about 3% of the profiles of cells showed glycogen, and by 24 hr half of the hepatocytes had glycogen. Addition of insulin plus glucose induced glycogen synthesis in 82% of the cells after 6 hr, and by 24 hr almost every cellular profile showed glycogen particles. Morphologically, glycogen accumulation was similar whether the cells were stimulated by high glucose or by glucose plus insulin: glycogen granules appeared in restricted regions of the cytoplasm, which were rich in smooth endoplasmic reticulum (SER), and peroxisomes were found close to the newly deposited glycogen particles. At maximum glycogen accumulation the association of SER and peroxisomes with glycogen was less obvious. Glycogenolysis induced by incubation of glycogen-rich hepatocytes with glucagon resulted in proliferation of SER in the glycogen regions of the cells. These observations are compatible with the concept of regions in the hepatocyte cytoplasm specialized for glycogen metabolism. Possible roles for SER and peroxisomes found near glycogen particles and other organelles in hepatic glycogen metabolism are discussed.
Anat Rec 1990 Jul
PMID:Glycogen metabolism in cultured chick hepatocytes: a morphological study. 219 38

The cytoarchitecture and immunocytochemical distribution of neuropeptides (corticotropin-releasing factor, CRF; neuropeptide Y, NPY; oxytocin, OXY; vasopressin, VP; and vasoactive intestinal polypeptide, VIP) were studied in the hypothalamic suprachiasmatic nuclei (SCN) in male and female ground squirrels of two species (Spermophilus tridecemlineatus and S. richardsonii). Immunoreactive (IR) perikarya were found in sections incubated with VP or VIP antisera. VP-IR cell bodies were seen in the dorsal and medial parts of the nucleus in colchicine-treated animals. IR fibers were distributed throughout the SCN. In the ventral part of the nucleus, VIP-IR cells were seen in untreated animals and were more pronounced in colchicine-treated animals. VIP-IR fibers and terminals form a dense plexus throughout the nucleus. Furthermore, NPY-IR terminals and fibers with multiple varicosities, but no IR perikarya, were present in the suprachiasmatic nuclei. Within the borders of the SCN, no cell bodies or fibers were stained with CRF or OXY antisera in any animal.
Anat Rec 1989 Dec
PMID:Immunohistochemical evidence for the presence of neuropeptides in the hypothalamic suprachiasmatic nucleus of ground squirrels. 258 47

Biopsies of the pancreas head, tail, and uncinate regions of four baboons were processed for immunocytochemical (ICC) studies by using avidin-biotin-peroxidase label for light microscopy (LM). Toluidine-blue- or methylene-blue-stained 0.5-micron sections of nonosmicated resin-embedded tissue were viewed to locate areas of suitable islets. For ICC investigations, batches 10 microns apart of ten consecutive 1-micron sections throughout ten islets from each of the three regions were immunolabelled for LM. Four slides in each batch were immunolabelled consecutively for insulin, glucagon, somatostatin, and pancreatic polypeptide, the fifth acting as one of the range of controls in each batch. The number of each of the four cell types was counted in at least ten immunolabelled islets from each of the pancreas heads, uncinate portions, and tails. The uncinate region and not the head, as in most mammals, was found to contain significantly higher numbers of pancreatic polypeptide (PP) cells and lower numbers of A (glucagon) and D (somatostatin) cells (P less than .001). The PP cells occurred in clumps and not as described in other mammals as part of the mantle of A, D, and PP cells. PP and A cell numbers were significantly different for each region (P less than .001), being lowest in the head for PP and in the uncinate process for A cells. D cell distribution was similar to that of the A cells whilst a significantly smaller number of B (insulin) cells was found in the tail compared with other regions (P less than .001).
Anat Rec 1987 Feb
PMID:Distribution of cell types of the islets of Langerhans throughout the pancreas of the Chacma baboon. 288 14

Biopsies of the pancreas head, tail, and uncinate regions of 6 Chacma baboons (Papio ursinus) were processed for ultrastructural and immunocytochemical (ICC) studies using avidin-biotin peroxidase label for light microscopy (LM) and immunogold for electron microscopy (EM). Survey 0.5 micron sections of Spurrs resin embedded tissue revealed areas of suitable islets. Thin 100-nm sections were then cut and stained from the osmicated blocks for ultrastructural studies. For ICC investigations, 1 micron sections were immunolabeled for LM before areas were selected for thin sectioning for ultrastructural immunolabeling. The baboon endocrine pancreas ultrastructure was found to be similar to that of other mammals with minor differences in islet and secretory granule size and shape and in electron opacity of the secretory granule cores. Insulin glucagon, somatostatin and pancreatic polypeptide (PP) producing cells were described. A small number of cells were seen to contain both glucagon and PP and some D cells were observed to contain a few granules with both the appearance and immunoreactivity of A cell secretory granules. Statistical analysis of 100 secretory granule diameters of each of the 4 cell types in 6 baboons revealed significant differences (p less than 0.001) in size between all but those of the A and D cells. The insulin precursor subunit, C-peptide, and the glucagon precursor, glicentin, were each found together with the final hormone product in their respective secretory granules. The precursors were often located toward the periphery of the secretory granule, suggesting that the conversion of precursor to active hormone may be membrane associated. A nonrandom topographical association was observed between A and D cells, suggesting a strong functional implication.
Anat Rec 1987 May
PMID:Morphology and endocrine production of cells in the islets of Langerhans of the Chacma baboon. 288 75

Fetal rat hepatocytes (22-day-old, full-term) in vivo were homogeneous in ultrastructure and glucose 6-phosphatase (G6Pase) distribution throughout the liver acinus. These cells were isolated and cultured for 17 days in Williams medium E containing 10% fetal calf serum, dexamethasone, insulin, and glucagon. Heterogeneity among hepatocytes appeared progressively during culture. There were variations in numbers of binucleated cells, cytoplasmic ultrastructure (e.g., in the distribution of glycogen and the quantity of ultrastructure (e.g., in the distribution of glycogen and the quantity of mitochondria), and intensity of histochemical reactivity for G6Pase. The cells could be classified generally into two types: type I cells had some characteristics of periportal hepatocytes and type II cells those of centrolobular hepatocytes in in vivo adult liver. The results show that a functional and structural heterogeneity can be formed among fetal hepatocytes in monolayer culture without differences in supply of oxygen, nutrients, and hormones. A hidden heterogeneity might already exist among hepatocytes in full-term fetuses even though it cannot be detected ultrastructurally or cytochemically.
Anat Rec 1985 Oct
PMID:A functional and structural heterogeneity is formed among fetal rat hepatocytes during culture. 300 Feb 23

The cytochemical localization of alkaline phosphatase (ALPase) activity and the autoradiographic distribution of glucagon receptors were examined in the plasma membrane of cultured mouse hepatocytes. After 24 hours of culture, ALPase activity was exclusively localized on the plasma membrane in areas of cell-cell contact, and glucagon receptors were more numerous in the plasma membrane at the periphery of re-formed cell trabeculae. These results indicate that plasma membrane regionalization of hepatocytes, lost by cell isolation, reappeared during culture. The cells maintained this plasma membrane regionalization until 48 hours of culture. By 72 hours of culture, however, ALPase activity was seen on the external surface of all regions of plasma membrane, and the glucagon receptors decreased markedly in number and became scattered in all regions of plasma membrane. Thus, the re-formed plasma membrane regionalization disappeared in the cells by 72 hours of culture.
Anat Rec 1986 Jan
PMID:Plasma membrane reregionalization in cultured mouse hepatocytes. 300 46

The distribution of glucagon and pancreatic polypeptide was studied immunocytochemically in rat pancreas at both light and electron microscopic levels. My earlier observation that these two peptides are distributed in three cell types--cells containing glucagon, cells containing pancreatic polypeptide, and cells containing both--was confirmed at the electron microscopic level. In the glucagon-pancreatic polypeptide cells, the immunoreactivities of the two peptides were present in the same secretion granules. In addition, these glucagon and pancreatic polypeptide-containing granules were morphologically distinct from glucagon granules but similar to pancreatic polypeptide granules and somatostatin granules.
Anat Rec 1985 Jul
PMID:Electron microscopic immunocytochemical localization of glucagon and pancreatic polypeptide in rat pancreas: characterization of a population of islet cells containing both peptides. 390 23


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