scholarly journals Attenuated processing of proglucagon and glucagon-like peptide-1 in carboxypeptidase E-deficient mice

2001 ◽  
Vol 169 (3) ◽  
pp. 595-602 ◽  
Author(s):  
L Friis-Hansen ◽  
KA Lacourse ◽  
LC Samuelson ◽  
JJ Holst
Keyword(s):  
Great Reduction ◽  
Prohormone Convertase ◽  
Adult Onset ◽  
Tissue Specific ◽  
Carboxypeptidase E ◽  
Mild Diabetes ◽  
Obesity Phenotype ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Deficient Mice

The maturation of many peptide hormones is attenuated in carboxypeptidase E (CPE)-deficient fat/fat mice, leading to a slowly developing, adult-onset obesity with mild diabetes. To determine the contribution of the hormones generated from the proglucagon precursor to this phenotype, we studied the tissue-specific processing of glucagon and glucagon-like peptide-1 (GLP-1) in these mice. In all tissues examined there was a great reduction in mature amidated GLP-1. Furthermore, a lack of CPE attenuates prohormone convertase processing of proglucagon in both the pancreas and the intestine. These findings suggest that defects in proglucagon processing together with other endocrine malfunctions could contribute to the diabetic and obesity phenotype in fat/fat mice.

Glucagon-like peptide 1 undergoes differential tissue-specific metabolism in the anesthetized pig

1996 ◽  
Vol 271 (3) ◽  
pp. E458-E464 ◽  
Author(s):  
C. F. Deacon ◽  
L. Pridal ◽  
L. Klarskov ◽  
M. Olesen ◽  
J. J. Holst
Keyword(s):  
Immunosorbent Assay ◽  
Half Life ◽  
Biologically Active ◽  
Enzyme Linked Immunosorbent Assay ◽  
Metabolic Clearance ◽  
Tissue Specific ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Plasma Half Life ◽  
Differential Tissue

Glucagon-like peptide 1 (GLP-1) metabolism was studied in halothane-anesthetized pigs (n = 7) using processing-independent (PI) and COOH-terminal (C) radioimmunoassays (RIA) and an enzyme-linked immunosorbent assay (ELISA) specific for biologically active GLP-1. Renal extraction of endogenous GLP-1 was detected by PI-RIA (33.1 +/- 13.3%) and C-RIA (16.0 +/- 6.3%) and by all assays during GLP-1 infusion (ELISA, 69.4 +/- 6.3%; PI-RIA, 32.6 +/- 7.3%; C-RIA, 43.7 +/- 3.4%), indicating substantial fragmentation. Hepatic and pulmonary degradation were undetectable under basal conditions, but exogenous GLP-1 elimination by the liver (43.6 +/- 8.9%) and lungs (10.1 +/- 3.2%) was measured by ELISA, suggesting primarily NH2-terminal degradation. Endogenous GLP-1 extraction by the hindleg was only detected by C-RIA (16.0 +/- 6.3%). During GLP-1 infusion, greater hindleg extraction was measured by ELISA (38.5 +/- 6.8%) and C-RIA (33.0 +/- 6.4%) than by PI-RIA (11.4 +/- 3.2%), indicating limited degradation at each terminus or more substantial COOH-terminal degradation. A shorter (P < 0.01) plasma half-life was revealed by ELISA (1.5 +/- 0.4 min) than by PI-RIA (4.5 +/- 0.6 min) or C-RIA (4.1 +/- 0.5 min). Metabolic clearance rates measured by PI-RIA (20.0 +/- 3.8 ml.min-1.kg-1) and C-RIA (15.5 +/- 1.6 ml.min-1.kg-1) were shorter (P < 0.01) than that measured by ELISA (106.8 +/- 14.7 ml.min-1.kg-1). Tissue-specific differential metabolism of GLP-1 occurs, and NH2-terminal degradation, rendering GLP-1 inactive, is particularly important in its clearance.

1784-P: Liraglutide Treatment Stimulates Alpha Cells to Produce Glucagon-Like Peptide-1 via Expression of Prohormone Convertase 1/3 in Mice and Human

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1784-P
Author(s):  
MRIDUSMITA SAIKIA ◽  
MARLENA M. HOLTER ◽  
DARLINE GARIBAY ◽  
ADOLFO GARCIA-OCANA ◽  
CHARLES G. DANKO ◽  
...  
Keyword(s):  
Prohormone Convertase ◽  
Alpha Cells ◽  
Prohormone Convertase 1 ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Uncoupling protein 2 negatively regulates glucose-induced glucagon-like peptide 1 secretion

2012 ◽  
Vol 48 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Hongjie Zhang ◽  
Jing Li ◽  
Xiangying Liang ◽  
Yun Luo ◽  
Ke Zen ◽  
...  
Keyword(s):  
Cell Model ◽  
Uncoupling Protein ◽  
Uncoupling Protein 2 ◽  
Mrna Levels ◽  
Incretin Hormone ◽  
Mucosal Layer ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Deficient Mice

It is known that endogenous levels of the incretin hormone glucagon-like peptide 1 (GLP1) can be enhanced by various secretagogues, but the mechanism underlying GLP1 secretion is still not fully understood. We assessed the possible effect of uncoupling protein 2 (UCP2) on GLP1 secretion in mouse intestinal tract and NCI-H716 cells, a well-characterized human enteroendocrine L cell model. Localization of UCP2 and GLP1 in the gastrointestinal tract was assessed by immunofluorescence staining. Ucp2 mRNA levels in gut were analyzed by quantitative RT-PCR. Human NCI-H716 cells were transiently transfected with siRNAs targeting UCP2. The plasma and ileum tissue levels of GLP1 (7–36) amide were measured using an ELISA kit. UCP2 was primarily expressed in the mucosal layer and colocalized with GLP1 in gastrointestinal mucosa. L cells secreting GLP1 also expressed UCP2. After glucose administration, UCP2-deficient mice showed increased glucose-induced GLP1 secretion compared with wild-type littermates. GLP1 secretion increased after NCI-H716 cells were transfected with siRNAs targeting UCP2. UCP2 was markedly upregulated in ileum tissue from ob/ob mice, and GLP1 secretion decreased compared with normal mice. Furthermore, GLP1 secretion increased after administration of genipin by oral gavage. Taken together, these results reveal an inhibitory role of UCP2 in glucose-induced GLP1 secretion.

scholarly journals TNF signaling impacts glucagon-like peptide-1 expression and secretion

2018 ◽  
Vol 61 (4) ◽  
pp. 153-161 ◽  
Author(s):  
Sufang Chen ◽  
Wei Wei ◽  
Minjie Chen ◽  
Xiaobo Qin ◽  
Lianglin Qiu ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Metabolism ◽  
Glucose Tolerance ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Deficient Mice

Numerous studies have implicated tumor necrosis factor α (TNFα) in the pathogenesis of type 2 diabetes. However, the role of its primary receptor, TNF receptor 1 (TNFR1), in homeostatic regulation of glucose metabolism is still controversial. In addition to TNFα, lymphotoxin α (LTα) binds to and activates TNFR1. Thus, TNFα and LTα together are known as TNF. To delineate the role of TNF signaling in glucose homeostasis, the present study ascertained how TNF signaling deficiency affects major regulatory components of glucose homeostasis. To this end, normal diet-fed male TNFR1-deficient mice (TNFR1−/−), TNFα/LTα/LTβ triple-deficient mice (TNF/LT∆3) and their littermate controls were subjected to intraperitoneal glucose tolerance test, insulin tolerance test and oral glucose tolerance test. The present results showed that TNFR1−/− and TNF/LT∆3 mice vs their controls had comparable body weight, tolerance to intraperitoneal glucose and sensitivity to insulin. However, their tolerance to oral glucose was significantly increased. Additionally, glucose-induced insulin secretion assessments revealed that TNFR1 or TNF/LT deficiency significantly increased oral but not intraperitoneal glucose-induced insulin secretion. Consistently, qPCR and immunohistochemistry analyses showed that TNFR1−/− and TNF/LT∆3 mice vs their controls had significantly increased ileal expression of glucagon-like peptide-1 (GLP-1), one of the primary incretins. Their oral glucose-induced secretion of GLP-1 was also significantly increased. These data collectively suggest that physiological TNF signaling regulates glucose metabolism primarily through effects on GLP-1 expression and secretion and subsequently insulin secretion.

scholarly journals Trafficking of Mutant Carboxypeptidase E to Secretory Granules in a β-Cell Line Derived from Cpefat/Cpefat Mice

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 292-298 ◽  
Author(s):  
Niamh X. Cawley ◽  
Yazmin M. Rodriguez ◽  
Alex Maldonado ◽  
Y. Peng Loh
Keyword(s):  
Cell Line ◽  
Secretory Pathway ◽  
Secretory Granules ◽  
Prohormone Convertase ◽  
Β Cell ◽  
Carboxypeptidase E ◽  
Prohormone Convertase 2 ◽  
Glucagon Like Peptide 1 ◽  
Regulated Secretory Pathway ◽  
The Stability

Abstract We have reinvestigated the stability and intracellular routing of mutant carboxypeptidase E in NIT3 cells, a pancreatic β-cell line derived from the Cpefat/Cpefat mouse. Pulse-chase experiments demonstrated that this protein has a half-life of approximately 3 h in these cells and that up to 45% of the proCPE(202) can escape degradation by the proteosome. In double-label immunofluorescence microscopy, a portion of the mutant CPE did not colocalize with calnexin, an endoplasmic reticulum marker, but was found in prohormone convertase 2-containing secretory granules, demonstrating that it had escaped degradation and arrived at a post-Golgi compartment. The mutant CPE as well as prohormone convertase 2 were secreted into the medium in a stimulated manner by treatment with the physiological secretagogue, glucagon-like peptide-1, consistent with its presence in granules of the regulated secretory pathway. The presence of mutant carboxypeptidase E in granules supports a potential role for its involvement as a sorting/retention receptor in the trafficking of proinsulin to the regulated secretory pathway.

scholarly journals Peptide production and secretion in GLUTag, NCI-H716, and STC-1 cells: a comparison to native L-cells

2016 ◽  
Vol 56 (3) ◽  
pp. 201-211 ◽  
Author(s):  
Rune Ehrenreich Kuhre ◽  
Nicolai Jacob Wewer Albrechtsen ◽  
Carolyn Fiona Deacon ◽  
Emilie Balk-Møller ◽  
Jens Frederik Rehfeld ◽  
...  
Keyword(s):  
Cell Lines ◽  
Peptide Yy ◽  
Prohormone Convertase ◽  
Basal Secretion ◽  
Human Gut ◽  
Hormone Production ◽  
L Cells ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Peptide Secretion

AbstractGLUTag, NCI-H716, and STC-1 are cell lines that are widely used to study mechanisms underlying secretion of glucagon-like peptide-1 (GLP-1), but the extent to which they resemble native L-cells is unknown. We used validated immunoassays for 14 different hormones to analyze peptide content (lysis samples;n= 9 from different passage numbers) or peptide secretion in response to buffer (baseline), and after stimulation with 50 mM KCl or 10 mM glucose + 10 µM forskolin/3-isobutyl-1-methylxanthine (n= 6 also different passage numbers). All cell lines produced and processed proglucagon into GLP-1, GLP-2, glicentin, and oxyntomodulin in a pattern (prohormone convertase (PC)1/3 dependent) similar to that described for human gut. All three cell lines showed basal secretion of GLP-1 and GLP-2, which increased after stimulation. In contrast to freshly isolated murine L-cells, all cell lines also expressed PC2 and secreted large amounts of pancreatic glucagon. Neurotensin and somatostatin storage was low and secretion was not consistently increased by stimulation. STC-1 cells released more glucose-dependent insulinotropic polypeptide than GLP-1 at baseline (P< 0.01) and KCl elevated its secretion (P< 0.05). Peptide YY, which normally co-localizes with GLP-1 in distal L-cells, was not detected in any of the cell lines. GLUTag and STC-1 cells also expressed vasoactive intestinal peptide, but none expressed pancreatic polypeptide or insulin. GLUTag contained and secreted large amounts of CCK, while NCI-H716 did not store this peptide and STC-1 contained low amounts. Our results show that hormone production in cell line models of the L-cell has limited similarity to the natural L-cells.

Gut carbohydrate inhibits GIP secretion via a microbiota/SCFA/FFAR3 pathway

2018 ◽  
Vol 239 (3) ◽  
pp. 267-276 ◽  
Author(s):  
Eun-Young Lee ◽  
Xilin Zhang ◽  
Junki Miyamoto ◽  
Ikuo Kimura ◽  
Tomoaki Taknaka ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Portal Vein ◽  
Glucose Transporter ◽  
Short Chain Fatty Acids ◽  
Germ Free ◽  
Glucosidase Inhibitor ◽  
Glucosidase Inhibitors ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Deficient Mice

Mechanisms of carbohydrate-induced secretion of the two incretins namely glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are considered to be mostly similar. However, we found that mice exhibit opposite secretory responses in response to co-administration of maltose plus an α-glucosidase inhibitor miglitol (maltose/miglitol), stimulatory for GLP-1, as reported previously, but inhibitory for GIP. Gut microbiota was shown to be involved in maltose/miglitol-induced GIP suppression, as the suppression was attenuated in antibiotics (Abs)-treated mice and abolished in germ-free mice. In addition, maltose/miglitol administration increased plasma levels of short-chain fatty acids (SCFAs), carbohydrate-derived metabolites, in the portal vein. GIP suppression by maltose/miglitol was not observed in mice lacking a SCFA receptor Ffar3, but it was normally seen in Ffar2-deficient mice. Similar to maltose/miglitol administration, co-administration of glucose plus a sodium glucose transporter inhibitor phloridzin (glucose/phloridzin) induced GIP suppression, which was again cancelled by Abs treatment. In conclusion, oral administration of carbohydrates with α-glucosidase inhibitors suppresses GIP secretion through a microbiota/SCFA/FFAR3 pathway.

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