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 objective of this study was to examine if RU486, a corticosteroid antagonist, modified hepatocyte metabolism and blocked the metabolic effects of exogenously administered cortisol in rainbow trout (Oncorhynchus mykiss). The fish were given a single intraperitoneal implant of either coconut oil alone or coconut oil containing RU486 (100 mg.kg-1), cortisol (100 mg.kg-1), or a combination of RU486 and cortisol and were sampled 7 days postimplantation. The RU486 implants had no effect on plasma cortisol and glucose concentrations, hepatocyte glycogen content, and total glucose production, but increased in vitro hepatocyte glycogen breakdown. Cortisol implantation had no effect on plasma glucose concentration, hepatocyte glycogen content, glycogen breakdown, or total glucose production, while it significantly increased alanine oxidation and gluconeogenesis in rainbow trout hepatocytes. Hepatocyte responsiveness to epinephrine and glucagon stimulation of total glucose production was not modified by either RU486 or cortisol treatment, whereas the insulin response on total glucose production was decreased with cortisol. RU486 treatment modified hepatocyte glycogen metabolism and blocked the cortisol-induced increases in alanine gluconeogenesis and glycogen mobilization for endogenous use by the hepatocytes. These results indicate that cortisol enhances the metabolic potential of hepatocytes, thereby adapting the fish to cope with stress. This study provides further validation of RU486 as a tool for studying metabolic actions of cortisol in fish.
Gen Comp Endocrinol 1994 Oct
PMID:The effects of cortisol on hepatocyte metabolism in rainbow trout: a study using the steroid analogue RU486. 784 70

Previous studies have indicated that teleost fish appear to have two somatostatin genes. In salmonid fish, it is purported that gene I encodes for somatostatin-14 (SS-14), while gene II encodes for somatostatin-25 (sSS-25). In the present study, the physiological effects of SS-14 and sSS-25 on carbohydrate and lipid metabolism in rainbow trout, Oncorhynchus mykiss, were evaluated by in vivo administration of hormone and measuring resulting levels of specific metabolites and hormones present within tissues and plasma. Somatostatin-14 administration caused hyperglycemia without affecting liver glycogen content and increased plasma fatty acid (FA) levels in association with enhanced activity of the lipid mobilizing enzyme, triacylglycerol lipase (TG lipase). Somatostatin-14 injection also resulted in reduced hepatic glucose-6-phosphate dehydrogenase activity, which may indicate a decrease in glucose channeling through the pentose phosphate shunt. In addition, SS-14 reduced plasma glucagon concentration, while having no effect on plasma insulin levels. Salmon SS-25 elevated plasma glucose levels in association with reduced glycogen content and resulted in increased plasma FA levels accompanied by increased hepatic TG lipase activity. Salmon SS-25 injection also resulted in a reduction in plasma glucagon and insulin levels. These results indicate that SS-14 and sSS-25 are important regulators of carbohydrate and lipid metabolism in rainbow trout and that modulation of metabolic activity by these peptides may be accomplished, in part, by alterations in insulin and glucagon levels circulating in the plasma.
Gen Comp Endocrinol 1993 Oct
PMID:Differential effects of somatostatin-14 and somatostatin-25 on carbohydrate and lipid metabolism in rainbow trout Oncorhynchus mykiss. 790 64

The cell types within the endocrine pancreatic tissue and anterior intestine of larvae and juveniles of representatives of the two southern-hemisphere families (Mordaciidae and Geotriidae) were compared, using immunohistochemistry and antisera against insulin (lamprey, bovine), two somatostatins (SST-14, -34), two PP-family peptides (aPY, NPY), and salmon glucagon and glucagon-like peptide (GLP). Cells of the islets and some anterior intestinal cells in larval Mordacia mordax showed intense immunoreactivity (IR) to the two insulin antisera. In contrast, immunoreactivity to these antisera in the islets of larval Geotria australis was restricted to antibovine insulin and even then the staining was weak. The islet cells did not IR with other antisera, but IR to aPY and NPY antisera was noted in a few intestinal cells of both species and cells in the intestine of G. australis were positively stained with antiSST-14 and/or -34. The single islet organ of adults of both species consisted only of antiinsulin-IR, B cells, and D cells, which were IR with only antiSST-14. Although IR was not seen in islet tissue to antisera against aPY, NPY, glucagon, and GLP, four cell types were identified in the intestinal epithelium in both species based on their IR to these antisera and the two antiSSTs. A fifth cell type IR to the two insulin antisera was recognized in adult M. mordax. The types and IR of endocrine cells in the enteropancreatic system of two southern-hemisphere lamprey families are compared with those of the Petromyzontidae, the single family of holarctic lampreys. Differences are discussed in relation to variations in hormone processing and whether they are a consequence of varied ontogenic and phylogenetic history among the extant Petromyzontiformes.
Gen Comp Endocrinol 1993 Nov
PMID:An immunohistochemical study of enteropancreatic endocrine cells in larvae and juveniles of the southern-hemisphere lampreys Geotria australis and Mordacia mordax. 790 50

Renin-like activity (RLA) and angiotensin I-converting enzyme-like activity (ACELA), two key enzymes of the renin-angiotensin cascade (RAS), were sought in the dogfish rectal gland. RLA was 1.1 +/- 0.2 ng Ang I/mg protein/hr after incubation with porcine angiotensinogen and 0.8 +/- 0.1 ng Ang I/mg protein/hr after incubation with homologous plasma. ACELA was 7.22 +/- 1.08 and 8.87 +/- 1.9 nmol hippurate generated/min/mg protein respectively, at 0 and 37 degrees. The presence of these enzymes may indicate the presence of an endogenous RAS-like system in the rectal gland. Angiotensin II (Ang II) and atrial natriuretic peptide (ANP) binding sites were demonstrated autoradiographically in the subcapsular region of the gland, suggesting a possible interaction of the two hormones in the blind outer ends of the rectal gland tubules. Immunoreactivities toward Ang II, ANP, bombesin, vasoactive intestinal polypeptide (VIP), glucagon, and somatostatin were differentially localized in the rectal gland within three concentric zones with potentially different functional activities. In the capsule, there was a strong positive ir-glucagon reaction and a slightly weaker reaction for ir-somatostatin and VIP. In the blind outer ends of the tubules (in the subcapsular zone), strong immunoreactivity was present toward all the tested peptides except glucagon and somatostatin. In the inner zone and in the central canal, only a weak immunoreactivity toward Ang II and glucagon was observed.
Gen Comp Endocrinol 1994 Feb
PMID:Renin-like activity, angiotensin I-converting enzyme-like activity, and osmoregulatory peptides in the dogfish rectal gland. 790 83

The hormones of the endocrine pancreas are believed to play an important role in early development. The development of the pancreas and the appearance of hormone-producing cells during embryogenesis have been extensively studied in mammals and birds. Relatively little work has been done in other vertebrates, and there are no published studies regarding the order Crocodilia. Given the pivotal phylogenetic position of crocodilians, Alligator mississippiensis provides an interesting species in which to study the embryonic development of the endocrine pancreas. The aims of the present study were (1) to investigate the morphological development of the pancreas and (2) to determine the initial appearance and regional distribution of the pancreatic endocrine cells in the embryonic alligator. At each stage of development serial sections of pancreatic tissue were stained with hematoxylin and eosin to aid in morphological description. Using immunocytochemistry sections were stained to detect the presence of insulin, glucagon, somatostatin, and pancreatic polypeptide. The dorsal pancreatic bud was first observed at stage 8, coincident with the appearance of insulin-containing and glucagon-containing cells. Somatostatin-containing cells were first detected at stage 10. At stage 13 the ventral pancreatic bud was first observed. At stage 14 the dorsal and ventral pancreatic buds fused and insulin, glucagon, and somatostatin were found throughout the pancreas. Not until stage 17 was pancreatic polypeptide first detected. Unlike the other hormones, pancreatic polypeptide was rare or absent in the dorsal region of the pancreas. In later stages of development, somatostatin-containing cells were the most abundant and constituted 35-40% of all hormone-containing cells. The sequence of appearance of insulin and glucagon found in the alligator is the same as that found in mammals and birds.
Gen Comp Endocrinol 1994 May
PMID:Ontogeny and regional distribution of hormone-producing cells in the embryonic pancreas of Alligator mississippiensis. 792 34

Hepatocytes were isolated from catfish (lctalurus melas) by conventional collagenase digestion. Sensitivities of liver cells isolated from the same fish to the glycogenolytic action of epinephrine, mammalian glucagon, catfish glucagon, catfish glucagon-like peptide, synthetic fragment 19-29 of anglerfish glucagon I, fragment 19-29 of anglerfish glucagon II, and anglerfish glucagon II were compared in two different systems: perifusion in a Bio-Gel P4 column and flask incubation. Both experimental procedures were continued for a total of 100-120 min, while hormones were applied simultaneously to both preparations for 10 min. Effluent fractions from the columns and incubation media from the flasks were collected for glucose determination. The hormonal effects were clearly enhanced in perifused cells compared to those in cells incubated in flasks, the effect being especially evident at physiological concentrations of hormones. The hormonal effects in both systems were dose-dependent. Epinephrine and mammalian glucagon (10 nM), applied separately to the same column, produced two different peaks, glucagon causing more glucose production than epinephrine. In the presence of 0.4 mM glucose in the perifusion system, hormonal effects were diminished, implying that glucose accumulation during incubation of liver cells in flasks might affect hormonal effects. The results obtained in this study indicate that piscine hepatocytes suspended and perifused in a Bio-Gel column are more sensitive to physiological concentrations of glycogenolytic hormones and may represent a new tool for experimental studies of fish liver metabolism and its hormonal regulation.
Gen Comp Endocrinol 1994 Jul
PMID:Hormone responsiveness of isolated catfish hepatocytes in perifusion system is higher than in flasks incubation. 792 55

The peptide hormone glucagon has been isolated from the islet tissue (Brockmann bodies) of the teleost Cottus scorpius (daddy sculpin) and sequenced. The sequence is HSEGTSNDYSKYLEDRKAQDFVQWLMNN differing at four positions from the glucagon found earlier in the same species by Conlon and coworkers (1987b, Eur. J. Biochem, 164, 117-122). Thus sculpin, in common with anglerfish, possesses two distinct glucagons. Comparative sequence data are presented as a phylogenetic tree.
Gen Comp Endocrinol 1993 Sep
PMID:A second glucagon in the pancreatic islets of the daddy sculpin Cottus scorpius. 822 71

Immunohistochemical studies have indicated that glucagon-containing cells are present in the intestinal mucosa of the agnathan Petromyzon marinus (sea lamprey) but are absent from the pancreas. Glucagon was isolated from an extract of intestinal tissue taken from specimens of sea lamprey during their parasitic phase. The primary structure of the peptide was established as: His-Ser-Glu-Gly-Thr5-Phe-Thr-Ser-Asp-Tyr10-Ser-Lys-Tyr-Leu- Glu15-Asn-Lys-Gln-Ala-Lys20-Asp-Phe-Val-Arg-Trp25-Leu- Met-Asn-Ala. This amino acid sequence shows 8 substitutions compared with that of mammalian glucagon but, with the exception of the COOH-terminal alanine residue, lamprey gut glucagon contains no structural features that have not been previously seen in glucagons isolated from the pancreata of gnathostomes. The amino acid sequence of lamprey glucagon-like peptide (GLP) demonstrates that the primary structure of this peptide has been less well conserved than that of glucagon. The sequence His-Ala-Asp-Gly-Thr5-Phe-Thr-Asn-Asp-Met10-Thr-Ser-Tyr- Leu-Asp15-Ala-Lys-Ala-Ala-Arg20-Asp-Phe-Val-Ser-Trp25- Leu-Ala-Arg-Ser-Asp30- Lys-Ser shows 16 amino acid substitutions compared with the corresponding region of mammalian GLP-1 and 15 substitutions compared with that of salmon GLP.
Gen Comp Endocrinol 1993 Jul
PMID:Primary structures of glucagon and glucagon-like peptide isolated from the intestine of the parasitic phase lamprey Petromyzon marinus. 840 97

1. ATP exerts multiple receptor-mediated effects on isolated hepatocytes: glycogenolysis through the activation of glycogen phosphorylase (cAMP-independent, IP3/calcium-mediated), inactivation of glycogen synthase, inhibition of the glucagon effect on cAMP, activation of phospholipase D. The fact that some of these effects can be selectively altered and that they are not, or differently, reproduced by some other analogues of ATP, suggests the presence of more than one receptor. (i) Pertussis toxin abolishes the anti-glucagon effect of ATP without affecting its glycogenolytic effect. (ii) Single cell calcium measurements reveal major differences between ATP and ADP, (iii) 2MeSATP and ADP beta S, in clear contrast to ATP, barely increase the levels of IP3 and their glycogenolytic effects is completely blocked by phorbol ester treatment of hepatocytes. (iv) 2MeSATP differs from ADP beta S since it has no anti-glucagon effect. 2. Effects of UTP on isolated hepatocytes so far do not show any difference with effects of ATP, suggesting interaction with the same receptor(s). 3. It is proposed that liver plasma membranes contain (at least) three different receptors mediating (a) the activation of phospholipase C, (b) the activation of phospholipase D and (c) the inhibition of adenylate cyclase.
Gen Pharmacol 1993 Mar
PMID:The complex interaction of ATP and UTP with isolated hepatocytes. How many receptors? 848 12

Pancreatic sections from diverse tetrapods, including various species of caviomorph rodents, were immunohistochemically investigated using two antisera which reacted with the N- and C-terminal portions of the glucagon molecule. While the antiserum against the N-terminal portion stained alpha cells in all the species studied, the antiserum against the C-portion failed to stain alpha cells in two caviomorphs of the Caviidae family (guinea pig and cuis) and in one of the Octodontidae family (degu). The observations in guinea pig and degu were expected, since their glucagons differ from those of many other tetrapods in the C-terminal portion of the molecule. In this paper, the cuis was added to these two species. It is noteworthy that among the caviomorphs studied herein (nine species), immunohistochemical differences were detected only in the three above-mentioned species and did not involve higher taxa, thus suggesting that these modifications are relatively recent in the evolution of this group of rodents.
Gen Comp Endocrinol 1995 Aug
PMID:Glucagon of caviomorphs and other tetrapods immunohistochemically investigated with two antisera against the N- and C-terminal portions of the molecule. 853 27


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