The Role of Leucine-Enkephalin on Insulin and Glucagon Secretion from Pancreatic Tissue Fragments of Normal and Diabetic Rats

2001 ◽  
Vol 109 (3) ◽  
pp. 223-229 ◽  
Author(s):  
E. Adeghate ◽  
A. S. Ponery
Keyword(s):  
Glucagon Secretion ◽  
Pancreatic Tissue ◽  
Diabetic Rats ◽  
Leucine Enkephalin ◽  
Insulin And Glucagon Secretion

scholarly journals The Difference δ-Cells Make in Glucose Control

Physiology ◽  
2018 ◽  
Vol 33 (6) ◽  
pp. 403-411 ◽  
Author(s):  
Mark O. Huising ◽  
Talitha van der Meulen ◽  
Jessica L. Huang ◽  
Mohammad S. Pourhosseinzadeh ◽  
Glyn M. Noguchi
Keyword(s):  
Glucose Control ◽  
Feedback Loop ◽  
Physiological Role ◽  
Glucagon Secretion ◽  
Negative Feedback Loop ◽  
Β Cells ◽  
Insulin And Glucagon Secretion ◽  
The Difference ◽  
Delta Cells

The role of beta and α-cells to glucose control are established, but the physiological role of δ-cells is poorly understood. Delta-cells are ideally positioned within pancreatic islets to modulate insulin and glucagon secretion at their source. We review the evidence for a negative feedback loop between delta and β-cells that determines the blood glucose set point and suggest that local δ-cell-mediated feedback stabilizes glycemic control.

scholarly journals Arginine-induced pancreatic hormone secretion during exercise in rats

1996 ◽  
Vol 81 (6) ◽  
pp. 2528-2533 ◽  
Author(s):  
Fethi Trabelsi ◽  
Jean-Marc Lavoie
Keyword(s):  
Hormone Secretion ◽  
Exercise Bout ◽  
Glucagon Secretion ◽  
Sympathoadrenal System ◽  
Control Groups ◽  
Insulin And Glucagon Secretion ◽  
Hormone Responses ◽  
Pancreatic Hormone ◽  
Hepatic Branch

Trabelsi, Fethi, and Jean-Marc Lavoie. Arginine-induced pancreatic hormone secretion during exercise in rats. J. Appl. Physiol. 81(6): 2528–2533, 1996.—The aim of the present investigation was to 1) determine whether arginine-induced pancreatic hormone secretion can be modified during an exercise bout, and 2) verify whether the sectioning of the hepatic branch of the vagus nerve can alter the arginine-induced insulin and glucagon secretion during exercise in rats. To this end, we studied the effects of an intraperitoneal injection of arginine (1 g/kg body mass) during an exercise bout (30 min, 26 m/min, 0% grade) on the pancreatic hormone responses. These effects were determined in one group of sham-operated exercising rats and compared with three control groups: one group of resting rats, one group of saline-injected exercising rats, and one group of hepatic-vagotomized exercising rats. Five minutes after the injection of arginine, significant ( P < 0.05) increases in insulin, glucagon, and C-peptide concentrations were observed in exercising as well as in resting rats. These responses were not, however, altered by the hepatic vagotomy and/or by the exercise bout. It is concluded that arginine is a potent stimulus of pancreatic hormone secretion during exercise, even though the sympathoadrenal system is activated. These results also indicate that a hepatic vagotomy does not seem to influence arginine-induced hormonal pancreatic responses and question the role of the putative hepatic arginoreceptors in the control of the pancreatic hormone secretion during exercise.

scholarly journals A possible mechanism for the anti-ketogenic action of alanine in the rat

1980 ◽  
Vol 190 (2) ◽  
pp. 323-332 ◽  
Author(s):  
Romano Nosadini ◽  
Harish Datta ◽  
Alan Hodson ◽  
K. George M. M. Alberti
Keyword(s):  
Ketone Body ◽  
Ketone Bodies ◽  
Regulatory System ◽  
Glucagon Secretion ◽  
Diabetic Rats ◽  
Metabolic Clearance ◽  
Endogenous Insulin ◽  
Feedback Cycle ◽  
Insulin And Glucagon Secretion ◽  
Acetoacetate Infusion

1. The anti-ketogenic effect of alanine has been studied in normal starved and diabetic rats by infusing l-alanine for 90min in the presence of somatostatin (10μg/kg body wt. per h) to suppress endogenous insulin and glucagon secretion. 2. Infusion of alanine at 3mmol/kg body wt. per h caused a 70±11% decrease in [3-hydroxybutyrate] and a 58±9% decrease in [acetoacetate] in 48h-starved rats. [Glucose] and [lactate] increased, but [non-esterified fatty acid], [glycerol] and [3-hydroxybutyrate]/[acetoacetate] were unchanged. 3. Infusion of alanine at 1mmol/kg body wt. per h caused similar decreases in [ketone body] (3-hydroxybutyrate plus acetoacetate) in 24h-starved normal and diabetic rats, but no change in other blood metabolites. 4. Alanine [3mmol/kg body wt. per h] caused a 72±9% decrease in the rate of production of ketone bodies and a 57±8% decrease in disappearance rate as assessed by [3-14C]acetoacetate infusion. Metabolic clearance was unchanged, indicating that the primary effect of alanine was inhibition of hepatic ketogenesis. 5. Aspartate infusion at 6mmol/kg body wt. per h had similar effects on blood ketone-body concentrations in 48h-starved rats. 6. Alanine (3mmol/kg body wt. per h) caused marked increases in hepatic glutamate, aspartate, malate, lactate and citrate, phosphoenolpyruvate, 2-phosphoglycerate and glucose concentrations and highly significant decreases in [3-hydroxybutyrate] and [acetoacetate]. Calculated [oxaloacetate] was increased 75%. 7. Similar changes in hepatic [malate], [aspartate] and [ketone bodies] were found after infusion of 6mmol of aspartate/kg body wt. per h. 8. It is suggested that the anti-ketogenic effect of alanine is secondary to an increase in hepatic oxaloacetate and hence citrate formation with decreased availability of acetyl-CoA for ketogenesis. The reciprocal negative-feedback cycle of alanine and ketone bodies forms an important non-hormonal regulatory system.

Insulin and glucagon secretion from isolated islets of Langerhans. The effects of calcium ionophores

1975 ◽  
Vol 150 (1) ◽  
pp. 88-96 ◽  
Author(s):  
J P Ashby ◽  
R N Speake
Keyword(s):  
Islets Of Langerhans ◽  
Hormone Secretion ◽  
Glucagon Secretion ◽  
Ionophore A23187 ◽  
Glucagon Release ◽  
Membrane Function ◽  
Isolated Islets Of Langerhans ◽  
Insulin And Glucagon Secretion ◽  
Perifused Islets

The role of Ca2+ in the secretion of insulin and glucagon was investigated by studying the effects of Ca2+ ionophores on hormone secretion from isolated perifused islets of Langerhans. Ionophore X537A (100 μM), which binds alkaline earth cations and also complexes some univalent cations, caused a rapid transient increase in insulin and glucagon secretion which was not dependent on the presence of Ca2+ in the perifusion medium. Ionophore A23187 (100 μM), which specifically binds bivalent cations at neutral pH values, similarly increased insulin secretion in complete and Ca2+-free medium, but only stimulated glucagon release in the presence of extracellular Ca2+. Since the stimulatory effects of both ionophores were associated with an increased Ca2+ flux in the islets, these experiments support the hypothesis that Ca2+ may trigger the release of insulin and suggest that it is also involved in the secretion of glucagon. The basal rate of both insulin and glucagon release was significantly increased when Ca2+ was omitted from the perifusion medium, but it is proposed that this finding may be due to adverse effects on cell-membrane function under these conditions.

Protective role of aqueous extract of Phyllanthus amarus on oxidative stress in pancreas of streptozotocin induced diabetic male Wistar rats

2016 ◽  
Vol 2 (1) ◽  
pp. 23 ◽  
Author(s):  
Sasi Bhusana Rao Bongu ◽  
Saisree Sagree ◽  
Vijayabharathi Gudapareddy ◽  
Malliah Putakala ◽  
Sreenivasulu Nukala ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Aqueous Extract ◽  
Reduced Glutathione ◽  
Protective Role ◽  
Pancreatic Tissue ◽  
Diabetic Rats ◽  
Phyllanthus Amarus ◽  
Glutathione S Transferase ◽  
Male Wistar Rats

Diabetes mellitus has been associated with oxidative stress. The present study was performed to investigate the pancreas protective activities of Phyllanthus amarus aqueous extract (PAAEt) in streptozotocin (STZ) induced diabetic rats. Oral administration of PAAEt (200mg/kg bw) to diabetic rats for 60 days significantly (p<0.05) decreased antioxidant enzymes such as glutathione peroxidase, glutathione-s-transferase, glutathione reductase, superoxide dismutase, catalase and depletion of reduced glutathione in panceas which illustrates that increased lipid peroxidation (107 %) was restored to control levels. Co-treatment with PAAEt revealed the therapeutic efficacy against oxidative stress in pancreatic tissue. Hence extract of this plant could be used as an adjuvant therapy for the prevention and/or management of diabetes.

REGULATION OF INSULIN AND GLUCAGON SECRETION FROM A HUMAN ISLET CELL ADENOMA

1977 ◽  
Vol 74 (2) ◽  
pp. 273-280 ◽  
Author(s):  
A. J. BONE ◽  
R. W. GUMPERT ◽  
S. L. HOWELL ◽  
J. SHELDON ◽  
M. TELLEZ-YUDILEVICH ◽  
...  
Keyword(s):  
B Cells ◽  
Islet Cell ◽  
Glucagon Secretion ◽  
Pancreatic Tissue ◽  
Tumour Cells ◽  
Human Islet ◽  
Insulin Content ◽  
Insulin Biosynthesis ◽  
Cell Adenoma ◽  
Insulin And Glucagon Secretion

The regulation of insulin biosynthesis, and insulin and glucagon secretion have been investigated in a human islet cell adenoma, by incubation of tumour fragments. Both biosynthesis and secretion of insulin were strongly stimulated by incubation of islet tumour cells in the presence of increasing glucose concentrations in the range 2–8 mmol/l. However, 20 mm-glucose or 20 mm-glucose plus isobutyl methylxanthine (IBMX), both of which provide potent secretagogues for normal B cells, failed to stimulate proinsulin biosynthesis and secretion from the tumour cells. Overall rates of secretion, expressed as a proportion of total insulin content, were up to 20-fold higher than those expected for normal pancreatic tissue. Glucagon secretion from the tumour was stimulated by low glucose concentrations; normal A cells also respond in this way under these conditions. However, no stimulation of glucagon secretion occurred in the presence of IBMX. There was therefore a major alteration in the regulation both of insulin and glucagon secretion, in that release of neither hormone was stimulated by cyclic AMP. Ultrastructural examination showed the tumour to be rather heterogeneous. A and B cells with normal storage granule content and structure were seen, as well as a rather larger number of B cells containing some granules of atypical appearance. The insulin content of the tumour (13 i.u./g wet wt) was consistent with 6–8% of the tumour cells being B cells.

The Role of GLP-1 Receptor Expressed in Pancreatic a Cells in Regulating Glucagon Secretion

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 355-OR ◽  
Author(s):  
YANQING ZHANG ◽  
KESHAB R. PARAJULI ◽  
GENEVIEVE E. SMITH ◽  
RAJESH GUPTA ◽  
WEIWEI XU ◽  
...  
Keyword(s):  
Glucagon Secretion ◽  
A Cells
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