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

Prenatal development of rat pancreatic endocrine cells was investigated by the immunoperoxidase technique and the following results were obtained: 1) Glucagon immunoreactive cells are first endocrine element of the pancreas appearing already on day 11 of gestation, when the dorsal pancreatic bud is still quite small and the ventral pancreatic primordium is hardly swollen out. Most of the glucagon reactive cells are located in the epithelium of the foregut and the dorsal pancreatic bud but a few of them are attached to the base of the epithelium from the outside. 2) Insulin and pancreatic polypeptide (PP) immunoreactive cells are first demonstrable in small cell clusters budding from the exocrine tubules on day 14, whereas somatostatin and gastrin reactive cells on day 17 and 18, respectively. These findings support the hypothesis that the majority of pancreatic endocrine cells is derived from the epithelium of the foregut. 3) PP reactive cells, appearing first on day 14, assume gradually a peripheral position in the growing islet of Langerhans. Immediately before birth they attain the population and flattened cell shape comparable to those in adult pancreas. Their counterpart in the duodenum is found as open type basal-granulated cells in the rat fetus. 4) Noteworthily, glucagon-like immunoreactivity is found in some neuron-like cells of the Auerbach's plexus between the muscle layers of the duodenum on day 19.
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PMID:Development of pancreatic endocrine cells in the rat fetus. 39 8

Hypoglycemia is known to stimulate human pancreatic polypeptide (hPP) secretion. To explore further the relationship between glucose availability and hPP release, we have examined the effect of tissue glucopenia induced by 2-deoxy-D-glucose (2-DG) on hPP plasma levels in normal subjects. As this glucose analogue activates the autonomic nervous system, we have also studied the influence of prior atropinization upon the hPP response to 2-DG. Moreover, we have tested the effects of iv epinephrine and norepinephrine on plasma hPP concentrations. Circulating glucagon was also measured. After the iv infusion of 2-DG (50 mg/kg), plasma hPP increased steeply from a fasting value of 104 +/- 24 pg/ml (SEM) to a peak of 2175 +/- 639 pg/ml at 45 min (P less than 0.01) and remained significantly elevated throughout the test. In contrast, prior injection of atropine (1 mg iv) lowered basal hPP levels and reduced conspicuously the hPP response to 2-DG. Epinephrine administration (6 micrograms/min for 60 min) did not significantly modify plasma hPP concentrations. However, 2 h after epinephrine withdrawal, circulating hPP showed a brisk elevation coinciding with the decline of glycemia to subbaseline values. During norepinephrine infusion (6 micrograms/min for 60 min), only a minor and transient increase of plasma hPP was found. Plasma glucagon rose significantly after 2-DG infusion, but this response was virtually absent in the atropine experiment. Whereas the well known glucagon tropic activity of epinephrine was evidenced, norepinephrine failed to exert an obvious effect on glucagonemia. Our data demonstrate that 2-DG induces a powerful stimulation of hPP secretion in normal subjects and suggest that this action is mediated in part, if not entirely, by the parasympathetic nervous system. On the other hand, a major role of the sympathoadrenal system in response of hPP to 2-DG or to hypoglycemia does not seem probable. Finally, the hyperglucagonemic effect of 2-DG seems also to be dependent on cholinergic transmission.
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PMID:Stimulation of pancreatic polypeptide and glucagon secretion by 2-deoxy-D-glucose in man: evidence for cholinergic mediation. 40 Jul 18

The effect of age and adiposity on fasting plasma levels of pancreatic polypeptide (HPP), glucagon (IRG), insulin (IRI) and glucose was examined in 263 healthy subjects between the ages of 20-69 yr. Mean plasma levels of hPP rose continuously from the third through the seventh decades. Mean plasma levels of IRG rose within the third and fourth decades but failed to rise further thereafter. Mean plasma levels of IRI did not change with age. Mean plasma levels of glucose rose by approximately 2 mg/dl . decade. The correlations of age with hPP, IRG, glucose, and adiposity were 0.47, 0.35, 0.25 (all P less than 0.01) and 0.15 (P less than 0.05), respectively. When adjustments were made for adiposity, the correlations of age with hPP, IRG, and glucose remained. Adiposity correlated with IRI, IRG, and glucose but when age correction was made, only the correlation of adiposity with IRI persisted. We conclude that: 1) age has a significant effect on fasting plasma levels of hPP and IRG; 2) the patterns of the age-related changes in hPP and IRG are not the same, suggesting that there are differences in the mechanism(s) by which age influences plasma levels of these two pancreatic hormones; and 3) age should be considered in the interpretation of fasting plasma levels of hPP and IRG.
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PMID:Effect of age on fasting plasma levels of pancreatic hormones in man. 40 Jul 40

1) In electively immuno-induced carcinomas of the exocrine pancrease in Mice, where A (glucagon) and B (insulin) endocrine cells persist, cells with a pancreatic polypeptide immunoreactivity are also detected, even in late evolution stages. These cells, like D cells, containing somatostatin, are localized only in the pancreatic remains surrounding the anaplasic carcinomatous tissue: islets, adenomatous parenchyma, and ductular epithelium. Ultrastructure of these cells shows their active elaboration of numerous chracteristic secretion granules. (2) Immunocytoenzymatic detection of gastrin is negative in the exocrine and endocrine pancreatic tissues. However one of the anti-gastrin sera used gives a positive reaction, in some carinomatous cells only. Does this immunoreactivity characterize a polypeptide specific to the pancreatic carcinomatous cell?
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PMID:[Presence of "pancreatic polypeptide" cells, and gastrin immunoreactivity in immuno-induced exocrine pancreas carcinoma]. 41 May 28

The peptides usually called gastrointestinal hormones belong to a broader group of regulatory substances distributed in many parts of the body and delivered to their targets not only by the blood but also by neural and paracrine paths. The neural, endocrine, and paracrine cells as a group might be called "regulator cells" and the chemical messengers they produce might be called "regulins." Twenty peptides have been isolated from the alimentary tract and pancreas: 12 have been sequenced, 4 have been partially sequenced, and 4 more have been identified only by immunoreactivity. Gastrin, gastric inhibitory peptide, glucagon, insulin, and secretin can be regarded as established hormones that are released into the blood by identified stimuli and produce identified physiological responses. The evidence for the hormonal status of cholecystokinin, pancreatic polypeptide, and motilin is incomplete but suggestive. The possible physiological roles of the other 12 peptides remain to be determined. If specific antagonists of these peptides can be found, they will greatly assist in elucidating the peptides' physiological roles.
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PMID:Chemical messengers: a view from the gut. 45 21

The influence of calcium on basal and acetylcholine-stimulated pancreatic polypeptide (PP) secretion was investigated in an isolated pancreatico-duodenal preparation and compared to the secretion of glucagon and insulin. The stimulatory effect of 5 mmol/liter calcium on PP release was of the same magnitude as that obtained by 5 mmol/liter arginine or 10 nmol/liter isoproterenol but only one fifth of the PP response to acetycholine (1 mumol/liter). All stimuli were equipotent with respect to insulin and glucagon release. The acetylcholine (1 mumol/liter)-stimulated PP release was almost identical at calcium concentrations of 1.3 and 6.3 mmol/liter, whereas glucagon release was calcium dependent, with higher responses at high (6.3 mmol/liter) than at normal (1.3 mmol/liter) calcium concentrations. In a calcium-depleted medium, acetylcholine induced a prompt, short-lived, but repeatable PP response, whereas no increase in glucagon or insulin was found. Further, when calcium influx into cells was blocked by excess magnesium (5.0 mmol/liter), the basal and acetylcholine (1 mumol/liter)-stimulated PP secretion was only inhibited by 12% (P = NS) and 42% (2P less than 0.05), respectively, whereas glucagon release was inhibited 56% (2P less than 0.001) and 76% (2P less than 0.01), respectively. It is concluded that the secretion of PP is influenced by calcium ions; however, the PP release is much less dependent on extracellular calcium ions than are insulin and glucagon secretions.
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PMID:The influence of calcium on the basal and acetylcholine-stimulated secretion of pancreatic polypeptide. 49 84

This dose-response study deals with the relative inhibitory effect of somatostatin on the acetylcholine-stimulated release of pancreatic polypeptide (PP), glucagon, and insulin from the isolated canine pancrease. Somatostatin in picomolar doses potently inhibited insulin and glucagon secretion, whereas PP secretion was relatively insensitive. Also, in the absence of acetylcholine, somatostatin exerted a preferential inhibition of the release insulin and glucagon compared with PP. These findings point to a physiologically important role of somatostatin for the secretion of insulin and glucagon, but probably not for PP.
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PMID:Differential sensitivity to somatostatin of pancreatic polypeptide, glucagon and insulin secretion from the isolated perfused canine pancreas. 51 83

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.
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PMID:Ontogeny and distribution of certain oendocrine cells in the human fetal large intestine. Histochemical and immunocytochemical studies. 51 32

The amylase/creatinine clearance ratio (Cam/Ccr ratio) was determined in 239 subjects. In 87 hospitalised patients without pancreatic disease (controls) the Cam/Ccr ratio was 3.02 +/- 0.69 (mean +/- ISD). The ratio was above the normal range in all patients with acute pancreatitis but was normal in those with chronic pancreatitis and carcinoma of the pancreas. In 18 patients with choledocholithiasis a raised ratio distinguished those with pancreatitis as assessed independently by the surgeon at laparotomy from those with a macroscopically normal pancreas. Raised Cam/Ccr ratios were also found in diabetics with ketoacidosis and in three patients with fulminant alcoholic liver disease. Though a positive correlation was found between the Cam/Ccr ratio and serum creatinine concentration, abnormally high ratios did not occur in 30 patients with chronic renal failure. A significant increase in Cam/Ccr ratios was produced in six healthy volunteers by intravenous injection of glucagon. However, it is unlikely that hyperglucagonaemia alone accounts for the increased Cam/Ccr ratio seen in acute pancreatitis, as no correlation was found between the clearance ratio and the plasma glucagon concentration in a series of patients. In two other patients in whom excess circulating pancreatic polypeptide was detected the Cam/Ccr ratio was normal. It is concluded that, in view of the sensitivity and relative specificity of finding an increased Cam/Ccr ratio in acute pancreatitis, its determination should be valuable clinically, especially in those cases of hyperamylasaemia where the cause is in doubt. The mechanism whereby the ratio is increased is unknown, and it is unlikely that either glucagon or pancreatic polypeptide is a major factor in its production.
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PMID:Mechanism and specificity of increased amylase/creatinine clearance ratio in pancreatitis. 60 90

Pancreatic polypeptide (PP)-containing cells were detected by using anti-bovine PP (BPP) serum in the pancreas and gastrointestinal tract of human fetuses, premature infants and in the pancreas, antrum and jejunum of adult man obtained by biopsy from patients with normal gastroduodenal endoscopy. The localization was established by studying the distribution of PP cells in comparison to the distribution of glucagon-, somatostatin- and insulin cells. The first PP cells are seen in the pancreas at 10 weeks of gestation. They are located preferentially in the lower part of the head of the pancreas. The specificity of immunocytological reaction was ascertained by the inhibition of the reaction by bovine pancreatic polypeptide, glucagon and insulin did not modify the immunocytological reaction.
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PMID:Immunohistochemical identification and localization of pancreatic polypeptide cells in the pancreas and gastrointestinal tract of the human fetus and adult man. 64 52


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