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 aim of this study was to compare the metabolic and hormonal effects of somatostatin to those of propranolol, a beta-adrenergic blocking agent known to reduce basal insulin secretion. For this purpose, 6 normal subjects received somatostatin (4 microgram/min) per 60 min and 6 subjects were infused with propranolol (0.08 mg/min). Somatostatin resulted in a significant decrease of basal insulin (p less than 0.05) and glucagon (p less than 0.01) and raised plasma FFA levels from a mean basal value of 417 +/- 24 muEq/1 (x +/- SEM) to 600 +/- 46 muEq/1 at 60 min (p less than 0.01). Propranolol significantly decreased basal insulin (p less than 0.05) and glucagon (p less than 0.05); FFA levels rose slightly at the end of propranolol administration (p less than 0.05). The levels of FFA which were significantly higher (p less than 0.025) during somatostatin as compared to those observed during propranolol, seem to suggest a role for this tetradecapeptide in lipid metabolism independent of its inhibiting action on islet hormone release.
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PMID:A comparative study of metabolic and hormonal responses to somatostatin and propranolol in man. 45 22

In healthy volunteers, the effects of intravenously administered glucagon on small intestinal function was investigated. Bolus doses resulting in plasma glucagon concentrations of greater than 800 pg/ml (5 min after injection) abolished jejunal contractions for 4.4 +/- 0.4 (SEM) min after a latency period of 49 +/- 4 sec. During continuous intravenous glucagon infusion, jejunal dilatation and increase in mean transit time (MTT) occurred at plasma levels greater than 720 pg/ml, while inhibition of water and electrolyte absorption was observed only with plasma glucagon concentrations of 1760 +/- 114 pg/ml. Under these conditions, the propulsion of fasting intestinal contents was slowed without change in flow rate. The observed effects cannot be attributed to the simultaneously occurring rise in plasma insulin and glucose concentrations. Short-term increases in circulating glucagon concentration inhibit intestinal tone, contractions, and propulsion with only a minor effect on water and electrolyte absorption limited to a narrow concentration range of plasma glucagon. Neither effect occurs at glucagon levels likely to occur under physiologic concentrations. The latency period preceding the abolition of jejunal contractions suggests that glucagon does not act directly on intestinal smooth muscle cells.
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PMID:Glucagon effects on the human small intestine. 45 37

The effect of portasystemic shunt surgery on basal immunoreactive glucagon (IRG) levels, metabolic clearance rate (MCR) and t 1/2 for glucagon decay, and basal systemic delivery rate (BSDR) of glucagon was investigated in paired studies in ten cirrhotic subjects. The degree of hepatocellular dysfunction and extent of portasystemic venous shunting was also recorded. Basal IRG levels were highest in the post-shunt (mean +/- SEM, 382 +/- 73 pg/ml) as compared to the pre-shunt (213 +/- 27 pg/ml; P less than 0.05) cirrhotic and control (53 +/- 13 pg/ml; P less than 0.005) groups. The MCR of glucagon was similar in control (13.0 +/- 1.3 ml/kg/min) and pre-shunt cirrhotic patients (13.3 +/- 1.7 ml/kg/min) but was significantly (P less than 0.02) decreased in the post-shunt cirrhotics (7.6 +/- 1.3 ml/kg/min). The t 1/2 for glucagon decay was similar in the control and cirrhotic groups. The BSDR, an estimate of pancreatic A cell secretion, was increased four-fold (P less than 0.01) in the pre-shunt (3042 +/- 454 pg/kg/min) and post-shunt (2518 +/- 535 pg/kg/min) cirrhotic groups, as compared to controls (750 +/- 244 pg/kg/min). It is concluded that (a) in the presence of cirrhosis, the magnitude of portasystemic shunting is important in determining the degree of hyperglucagonaemia; (b) in preshunt cirrhotics raised basal IRG levels are principally due to A cell hypersecretion of glucagon whereas in post-shunt cirrhotics riased IRG levels reflect both A cell hypersecretion and delayed clearance of glucagon; and (c) acute shunting of splanchnic venous blood away from the liver reduces the clearance of glucagon, suggesting that, in man, the liver contributes to the clearance of circulating glucagon.
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PMID:Glucagon metabolism in normal subjects and in cirrhotic patients before and after portasystemic venous shunt surgery. 51 79

The possible existence of circulating pancreatic type glucagon (immunoreactive glucagon as measured with a highly specific antibody) of extrapancreatic origin was investigated in 20-25 kg pigs after pancreatectomy. In intact conscious animals intravenous arginine infusions stimulated glucagon as well as insulin secretion, while blood glucose remained unaffected. Two weeks after pancreatectomy, and 48 hours after insulin withdrawal, basal glucagon and glucose concentrations were elevated (from 22 +/- 3.7 to 55 +/- 9.5 pmol/1 and 5.8 +/- 0.4 to 16.2 +/- 2.0 mmol/l, respectively), (mean +/- SEM), while insulin concentrations were either undetectable or very low. After pancreatectomy, however, glucagon concentrations no longer increased during arginine infusion. Gut type glucagon levels were not affected by pancreatectomy, and did not change during arginine infusion. When examined by gel filtration, plasma from unoperated pigs contained two components of pancreatic type glucagon, one coeluting with the glucagon marker, the other eluting earlier, probably reflecting larger molecular size. After pancreatectomy only this larger component was found in the plasma. The role of this component in the control of blood glucose is unknown.
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PMID:Absence of true pancreatic glucagon but persistence of circulating pancreatic glucagon-like immunoreactivity after pancreatectomy in pigs. 68 Mar 13

Fasting (24 h) normal dogs and depancreatized dogs were injected intravenously with highly purified porcine insulin (Actrapid) in the doses of 0.2 U/kg and 0.5 U/kg, respectively. Blood glucose decreased from 152 +/- 41 (SEM) mg/100 ml to 39 +/- 7 mg/100 ml in the depancreatized dog and from 95 +/- 3 mg/100 ml to 42 +/- 4 mg/100 ml in the normal animal. Using a specific antiserum for "pancreatic" glucagon, the circulating level of glucagon immunoreactivity did not rise from the basal value of 247 +/- 31 pg/ml in the depancreatized group whereas it rose significantly from 223 +/- 24 pg/ml to 321 +/- 41 pg/ml in the normal group. In contrast intravenous infusion of 7 g of arginine increased "pancreatic" glucagon immunoreactivity in both groups. Thus, extrapancreatic glucagon of the pancreatic type does not respond to hypoglycaemia but to arginine infusion.
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PMID:Lack of gastrointestinal glucagon response to hypoglycaemia in depancreatized dogs. 72 Jul 80

Circulating hormone and substrate levels were measured in 7 patients at regular intervals before, during and after pulmonary surgery. During surgery, cortisol and growth hormone were significantly elevated, pancreatic glucagon was unchanged and insulin was depressed. One and two days after surgery, growth hormone had almost returned to preoperative fasting values, but cortisol, insulin and glucagon levels were significantly increased. The mean insulin:glucagon molar ratio declined from a preoperative fasting value of 3.2 +/- 0.5 (+/- SEM) to 1.7 +/- 0.4 during operation but was within normal limits 1 and 2 days after surgery due to a parallel rise and fall in plasma insulin and glucagon. Plasma glucose was elevated both during operation and for several days thereafter, whereas free fatty acid levels were increased only during operation. Thus, there was no consistent relation between insulin:glucagon ratio or any of the hormone levels and the observed elevations in plasma glucose and free fatty acids. It is concluded that neither any of the hormones assayed nor the insulin:glucagon ratio was the primary determinant of plasma glucose and free fatty acid responses to surgery. Rather, fuel homeostasis appeared to result from the combined effects of glucagon, insulin, growth hormone, cortisol and adrenergic activity.
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PMID:Glucagon, insulin, cortisol, and growth hormone levels following major surgery: their relationship to glucose and free fatty acid elevations. 74 65

Glucagon was administered exogenously via a subcutaneous route to totally depancreatized adult mongrel dogs and studies were made with major emphasis on glucagon effect on the plasma glucose levels. 1. In the totally depancreatized dogs, the plasma glucose levels determined 90 minutes after glucagon injection (40 micrograms/kg s.c.). were compared with the pretreatment fasting plasma glucose levels. The rate of increase in the plasma glucose levels was 5.13 +/- 0.48 times (M +/- SEM) in dogs with low pretreatment level (lower than 100 mg/dl). In dogs with higher pretreatment levels (100-400 mg/dl), the increase was 1.62 +/- 0.40 times. And in dogs with the pretreatment levels higher than 400 mg/dl, the value was 0.90 +/- .07 times. 2. Ninety minutes after regular insulin injection (0.25 U/kg i.v.), glucagon was administered (40 micrograms/kg s.c.), and the changes in the plasma glucose levels were determined. 3. In totally depancreatized dogs, a transient increase in the plasma insulin level was noted when glucagon was administered (40 micrograms/kg s.c.) under infusion of a mixture of glucose and insulin. 4. There was no significant difference in the rate of disappearance of glucagon from the blood between normal and totally depancreatized dogs. 5. It is considered that glucagon would be useful for the treatment of hypoglycemia encountered after total pancreatectomy.
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PMID:Effect of exogenously administered glucagon on plasma glucose levels in totally depancreatized dogs. 74 92

This work was undertaken to study the effect of prednisolone on glucagon release in mouse pancreatic islets isolated by the collagenase technique. Pretreatment of the donors with prednisolone (0.2--0.3 mg daily) induced an increase in glucagon release both in the absence (1005+/-75, SEM, vs. 796+/-46 pg/10 islets/60 min, p=0.019) and in the presence of 7.5 mM arginine (1500+/-119 vs. 1236+/-61 pg/10 islets/60 min, p=0.05). The glucagon content of the islets was not modified by the treatment (28.6+/-1.1 vs. 28.0+/-1.1 ng/50 islets). The addition of prednisolone (5 - 10(-5) M) into the medium, failed to affect significantly glucagon secretion. In agreement with previous human studies, our data indicate that chronic glucocorticoid administration augments the secretory activity of the A-cell. This does not seem to be a result of increased glucagon synthesis nor a direct effect of glucocorticoids on the glucagon-releasing mechanism. Rather, environmental changes induced by these hormones could be responsible for A-cell hyperfunction.
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PMID:Enhanced glucagon secretion by pancreatic islets from prednisolone-treated mice. 78 66

The cholesterol-lowering effect of portacaval anastomosis in homozygous familial hypercholesterolemia suggested a study of lipid metabolism in cirrhotic patients after portasystemic anastomoses. Fasting serum cholesterol, triglycerides, insulin, and glucagon levels were obtained in 20 patients with alcoholic cirrhosis and portacaval anastomosis, and in 21 nonshunted subjects with cirrhosis. After 100 g of glucose, given orally, insulin and glucagon levels were measured. In the shunted patients serum cholesterol was higher than in the nonshunted subjects, 240 +/- 15 mg per 100 ml (mean +/- 1 SEM) versus 180 +/- 13 mg per 100 ml, P less than 0.01. Triglycerides were normal in both groups. Fasting insulin was elevated to a greater extent in the shunted patients with cirrhosis (36 +/- 5 muU per ml) than in the nonshunted patients (22 +/- 4 muU per ml), P less than 0.05. Two hours after glucose, insulin levels were also elevated to a greater extent in the shunted subjects (304 +/- 50 muU per ml) than in the nonshunted subjects (167 +/- 29 muU per ml), P less than 0.03. Fasting glucagon (corrected for interference factor) was elevated to a greater extent in the shunted subjects (204 +/- 35 pg per ml) than in the nonshunted subjects (80 +/- 19 pg per ml), P less than 0.01. The explanation for serum cholesterol elevation after surgical shunting in cirrhotics is unknown. Two possible hypotheses--the differential action of insulin and glucagon on cholesterol metabolism and the effects of shunting on the cirrhotic liver--are discussed.
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PMID:Serum lipids, insulin, and glucagon after portacaval shunt in cirrhosis. 83 May 79

Non-specific plasma effects may produce major errors in the estimation of true plasma pancreatic glucagon concentrations by radioimmunoassay. This has been circumvented by the production of glucagon-free plasma for each individual investigated, by means of glucagon antibody, coupled to sepharose beads. True fasting pancreatic glucagon levels (mean+/-SEM) in 18 healthy subjects (24+/-3 pg/ml) were significantly lower (p less than .005) than in 10 non-ketotic non-obese diabetics (38+/-3 pg/ml). It is suggested that, in the presence of decreased insulin-effect in the diabetic, this 55% glucagon elevation in diabetics may be of biological importance and contribute to the fasting hyperglycaemia.
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PMID:Glucagon levels in normal and diabetic subjects: use of a specific immunoabsorbent for glucagon radioimmunoassay. 83 98


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