Secretin and its C-terminal hexapeptide potentiates insulin release in mouse islets

1986 ◽  
Vol 250 (2) ◽  
pp. E107-E113 ◽  
Author(s):  
H. Kofod ◽  
B. Hansen ◽  
A. Lernmark ◽  
C. J. Hedeskov
Keyword(s):  
Glutamate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Insulin Release ◽  
Maximal Effect ◽  
Terminal Sequence ◽  
Terminal Part ◽  
Mouse Pancreatic Islets ◽  
Glutamate Dehydrogenase Activity ◽  
Mouse Islets

Peptides representing the C-terminal end of secretin were synthetized and their effects tested along with secretin on column-perifused isolated mouse pancreatic islets. Insulin release induced by 10 mmol/l D-glucose was potentiated by secretin tested in a concentration range of 0.01-10 micrograms/ml; the maximal effect was obtained with 1 microgram/ml secretin. This effect was mimicked by 50-500 micrograms/ml NH2-Leu-Leu-Gln-Gly-Leu-Val-NH2, [S-(22-27)], which represents an amidated C-terminal sequence of the secretin molecule. The consecutive smaller secretin C-terminal peptides had either no effects [Val-NH2, S-(24-27)] or only marginally [S-(26-27), S-(23-27)] potentiating effects on insulin release in the presence of 10 mmol/l D-glucose. The effects of secretin and S-(22-27) were not influenced by 2 mmol/l glutamine. The intact hormone and the five synthetic peptides as well as Val-NH2 had no stimulatory effect on islet glutamate dehydrogenase activity. In fact, S-(23-27), S-(24-27), and S-(25-27) inhibited the islet glutamate dehydrogenase activity, the activation by which amino acids and amino acid derivatives are known to elicit a potentiation of insulin release. Our results suggest that the C-terminal part is important to the marked potentiation of glucose-induced insulin release in vitro by secretin.

Glutamate dehydrogenase activity in normal and vitrified plants of Agave tequilana Weber propagated in vitro

1990 ◽  
Vol 22 (2) ◽  
pp. 147-151 ◽  
Author(s):  
Lizbeth Castro-Concha ◽  
Victor M. Loyola-Vargas ◽  
Jos� L. Chan ◽  
Manuel L. Robert
Keyword(s):  
Glutamate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Agave Tequilana ◽  
Glutamate Dehydrogenase Activity

Direct long-term effect of hydrocortisone on insulin and glucagon release from mouse pancreatic islets in tissue culture

1981 ◽  
Vol 96 (4) ◽  
pp. 498-504 ◽  
Author(s):  
J. Brunstedt ◽  
J. Høiriis Nielsen
Keyword(s):  
Tissue Culture ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Endocrine Function ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Long Term Effect ◽  
Mouse Pancreatic Islets ◽  
Pancreatic Endocrine Function ◽  
Mouse Islets

Abstract. The effects of glucocorticoids on the pancreatic endocrine function was studied in isolated mouse pancreatic islets maintained in tissue culture for 1 to 3 weeks. Following culture for 1 week without corticoid supplement acute experiments with hydrocortisone showed no significant effect on the glucose-induced insulin release at 10−8 to 10−5 mol/l hydrocortisone. When, however, the islets were cultured in the presence of hvdrocortisone, there was an increased insulin release to the medium in a dose-dependent manner, with the maximal effect at 10−7 mol/l hydrocortisone. The release of glucagon to the medium was not affected to the same degree, but showed a slight inhibition at increasing concentrations of hydrocortisone. Short-term experiments after the culture period showed that islets cultured for 3 weeks in the presence of 10−7 to 10−5 mol/l hydrocortisone had an enhanced insulin secretion in response to glucose. The islets did not show any statistically significant change in their insulin- and DNA-content after 3 weeks of culture with hydrocortisone, but a marked reduction in the content of glucagon was found with increasing concentrations of hydrocortisone. The present results suggest that physiological concentrations of hydrocortisone are of importance for mouse islets to maintain their insulin production in tissue culture.

scholarly journals Effect of interferon and double-stranded RNA on B-cell function in mouse islets of Langerhans

1985 ◽  
Vol 228 (1) ◽  
pp. 87-94 ◽  
Author(s):  
C J Rhodes ◽  
K W Taylor
Keyword(s):  
Insulin Release ◽  
Cell Function ◽  
Protein Biosynthesis ◽  
Insulin Biosynthesis ◽  
Double Stranded Rna ◽  
Mouse Pancreatic Islets ◽  
Mouse Islets ◽  
Stimulation Of ◽  
Slight Inhibition

The direct effects of alpha- and beta-interferons on isolated mouse pancreatic islets were investigated in vitro and found to be similar. After 7 h incubation with interferon concentrations above 350 units/ml, glucose-stimulated (pro)insulin biosynthesis was significantly inhibited, with only a slight inhibition of total protein biosynthesis. Inhibition could be abolished in the additional presence of an anti-interferon antibody. Interferon did not affect insulin release, total insulin content, or glucose oxidation of the islets. The stimulation of (pro)insulin biosynthesis by adenosine, D-glyceraldehyde, mannose, N-acetylglucosamine and leucine was also inhibited by interferon, with no effect on insulin release. At concentrations of dsRNA (double-stranded RNA) said to induce interferon (1-100 micrograms/ml), glucose-stimulated (pro)insulin biosynthesis was inhibited without significantly affecting insulin release. The dsRNA may itself inhibit stimulated (pro)insulin biosynthesis or may function indirectly by the induction of interferon.

Rapid depletion of somatostatin in isolated mouse pancreatic islets after treatment with cysteamine

1985 ◽  
Vol 110 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Birger Petersson ◽  
Claes Hellerström
Keyword(s):  
Pancreatic Islets ◽  
Insulin Release ◽  
Basal Insulin ◽  
Glucose Stimulation ◽  
Isolated Pancreatic Islets ◽  
Basal Release ◽  
Mouse Pancreatic Islets ◽  
Mouse Islets

Abstract. Cysteamine (CSH; β-mercaptoethylamine) is known to deplete pancreatic somatostatin without affecting the insulin or glucagon content. It may therefore be useful for studies of intra-islet regulation of hormone release. In the present study injection of CSH (60 mg/kg body weight) to mice decreased the somatostatin content of their isolated pancreatic islets to 50% in 1 h and 30% in 4 h as compared to islets of non-injected controls. Exposure of isolated mouse islets to CSH (100 μg/ml) for either 0.5 h followed by incubation in control medium for 3.5 h, or continuously for 4 h, decreased the somatostatin content to about 40% of the controls. There was no change in the islet content of insulin or glucagon. Islets pretreated with CSH (100 μg/ml) for 1 h in vitro showed a decreased glucose stimulation of both oxygen consumption and glucose oxidation. Measurements of insulin release after a similar preincubation of the islets indicated an increased basal release and an attenuated glucose stimulation. It is concluded that CSH rapidly decreases islet somatostatin both in vivo and in vitro. This depletion may lead to a loss of tonic inhibition by islet somatostatin on basal insulin release. It is, however, more plausible that the increased basal insulin release reflected a direct effect of CSH on the islet β-cells.

Abnormal platelet glutamate dehydrogenase activity and activation in dominant and nondominant olivopontocerebellar atrophy

1986 ◽  
Vol 19 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Sandro Sorbi ◽  
Stefano Tonini ◽  
Emiliana Giannini ◽  
Silvia Piacentini ◽  
Paolo Marini ◽  
...  
Keyword(s):  
Glutamate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Olivopontocerebellar Atrophy ◽  
Glutamate Dehydrogenase Activity

Identification and characterization of glutamate dehydrogenase activity in wild Lactococcus lactis isolated from raw milk cheeses

2017 ◽  
Vol 244 (4) ◽  
pp. 603-609 ◽  
Author(s):  
Luz P. Gómez de Cadiñanos ◽  
Carmen Peláez ◽  
M. Carmen Martínez-Cuesta ◽  
Tomás García-Cayuela ◽  
Teresa Requena
Keyword(s):  
Glutamate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Lactococcus Lactis ◽  
Raw Milk ◽  
Glutamate Dehydrogenase Activity ◽  
Identification And Characterization

L-leucine methyl ester stimulates insulin secretion and islet glutamate dehydrogenase

1983 ◽  
Vol 245 (4) ◽  
pp. E338-E346 ◽  
Author(s):  
P. Knudsen ◽  
H. Kofod ◽  
A. Lernmark ◽  
C. J. Hedeskov
Keyword(s):  
Insulin Secretion ◽  
Methyl Ester ◽  
Glutamate Dehydrogenase ◽  
Insulin Release ◽  
Methyl Esters ◽  
Tumor Cell Line ◽  
Fold Increase ◽  
Inhibitory Effect ◽  
Amino Acid Derivative ◽  
Mouse Pancreatic Islets

Column perifusion of collagenase-isolated mouse pancreatic islets was used to study the dynamics of insulin release in experiments lasting for several hours. The methyl esters of L-leucine and L-arginine were synthesized. Whereas L-arginine methyl ester (L-arginine OMe) had no effect, L-leucine OMe stimulated the release of insulin. The effect of L-leucine OMe was maximal at 5 mmol/liter. Whereas the Km for glucose-stimulated insulin release was unaffected by 1 mmol/liter L-leucine OMe, the maximal release of D-glucose was increased by the amino acid derivative that appeared more effective than L-leucine. L-Leucine OMe was also a potent stimulus of insulin release from the perfused mouse pancreas. In the presence of 10 mmol/liter L-glutamine, 1 mmol/liter L-leucine OMe induced a 50- to 75-fold increase in insulin release. A similar stimulatory effect was also observed in column-perifused RIN 5F cells, a cloned rat islet tumor cell line. A twofold increase in islet glutamate dehydrogenase activity was induced by 5 mmol/liter L-leucine OMe, a larger effect than that of L-leucine (P less than 0.02), whereas L-arginine OMe had a small inhibitory effect. We conclude that L-leucine OMe is a potent stimulus of insulin secretion and that its effect on the beta-cells may be exerted by activating islet glutamate dehydrogenase.

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