scholarly journals The Mitochondrial Citrate Carrier (CIC) Is Present and Regulates Insulin Secretion by Human Male Gamete

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1743-1754 ◽  
Author(s):  
Anna R. Cappello ◽  
Carmela Guido ◽  
Antonella Santoro ◽  
Marta Santoro ◽  
Loredana Capobianco ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Energy Metabolism ◽  
Acrosome Reaction ◽  
Male Gamete ◽  
Human Sperm ◽  
Morphological Evidence ◽  
Specific Substrate ◽  
Similar Action ◽  
Citrate Carrier ◽  
Glucose Stimulated Insulin Secretion

The mechanisms through which sperm manage their energy metabolism are poorly understood. The present study provides biochemical and morphological evidence that mitochondrial citrate carrier (CIC) is present in ejaculated human sperm and is restricted to the midpiece. The inhibition of CIC with the specific substrate analog 1,2,3-benzenetricarboxylate resulted in the reduction of cholesterol efflux, protein tyrosine phosphorylation, phospho-AKT, phospho-p60src, hyperactivated motility and acrosome reaction, suggesting a role for this mitochondrial carrier in sperm physiology. Furthermore, inhibition of CIC by 1,2,3-benzenetricarboxylate resulted in a reduction of glucose-stimulated insulin secretion and autocrine insulin secretion by sperm. Remarkably, blocking CIC also reduced glucose-6-phosphate dehydrogenase activity, probably in accordance with its regulation on insulin secretion. Capacitation and glucose metabolism were stimulated by glucose as well as citrate, the specific substrate of CIC, implying a similar action because glucose and citrate both induced insulin secretion by sperm. In the present finding, we discovered a new site of action for CIC in the regulation of metabolism, and it may be assumed that CIC works with other factors in the regulation of sperm energy metabolism to sustain capacitation process and acrosome reaction.

scholarly journals ARHGAP21 Acts as an Inhibitor of the Glucose-Stimulated Insulin Secretion Process

2020 ◽  
Vol 11 ◽  
Author(s):  
Sandra M. Ferreira ◽  
José M. Costa-Júnior ◽  
Mirian A. Kurauti ◽  
Nayara C. Leite ◽  
Fernanda Ortis ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Energy Metabolism ◽  
Cell Interaction ◽  
Tolerance Test ◽  
Functional Maturation ◽  
Secretion Process ◽  
Insulin Tolerance ◽  
Intracellular Calcium Dynamics ◽  
Glucose Stimulated Insulin Secretion ◽  
Adult Islet

ARHGAP21 is a RhoGAP protein implicated in the modulation of insulin secretion and energy metabolism. ARHGAP21 transient-inhibition increase glucose-stimulated insulin secretion (GSIS) in neonatal islets; however, ARHGAP21 heterozygote mice have a reduced insulin secretion. These discrepancies are not totally understood, and it might be related to functional maturation of beta cells and peripheral sensitivity. Here, we investigated the real ARHGAP21 role in the insulin secretion process using an adult mouse model of acute ARHGAP21 inhibition, induced by antisense. After ARHGAP21 knockdown induction by antisense injection in 60-day old male mice, we investigated glucose and insulin tolerance test, glucose-induced insulin secretion, glucose-induced intracellular calcium dynamics, and gene expression. Our results showed that ARHGAP21 acts negatively in the GSIS of adult islet. This effect seems to be due to the modulation of important points of insulin secretion process, such as the energy metabolism (PGC1α), Ca2+ signalization (SYTVII), granule-extrusion (SNAP25), and cell-cell interaction (CX36). Therefore, based on these finds, ARHGAP21 may be an important target in Diabetes Mellitus (DM) treatment.

Synchronized Microfluidic System to Dynamically Assess Pancreatic Islet Function beyond Glucose-Stimulated Insulin Secretion

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 2162-P
Author(s):  
STEPHAN NIEUWOUDT ◽  
RUTH MCDOWELL ◽  
HUI ZHANG ◽  
JOHN P. KIRWAN
Keyword(s):  
Insulin Secretion ◽  
Pancreatic Islet ◽  
Microfluidic System ◽  
Islet Function ◽  
Glucose Stimulated Insulin Secretion

scholarly journals In Vitro Studies to Assess the α-Glucosidase Inhibitory Activity and Insulin Secretion Effect of Isorhamnetin 3-O-Glucoside and Quercetin 3-O-Glucoside Isolated from Salicornia herbacea

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 483
Author(s):  
Dahae Lee ◽  
Jun Yeon Park ◽  
Sanghyun Lee ◽  
Ki Sung Kang
Keyword(s):  
Insulin Secretion ◽  
Cell Function ◽  
Ethanolic Extract ◽  
Ethyl Acetate Fraction ◽  
Gradient Elution ◽  
Glucosidase Activity ◽  
Β Cell Function ◽  
Glucose Stimulated Insulin Secretion ◽  
Salicornia Herbacea

In this study, we examined the effect of ethanolic extract of Salicornia herbacea (ESH), isorhamnetin 3-O-glucoside (I3G), quercetin 3-O-glucoside (Q3G), quercetin, and isorhamnetin on α-glucosidase activity and glucose-stimulated insulin secretion (GSIS) in insulin-secreting rat insulinoma (INS-1) cells. A portion of the ethyl acetate fraction of ESH was chromatographed on a silica gel by a gradient elution with chloroform and methanol to provide Q3G and I3G. ESH, Q3G, and quercetin inhibited α-glucosidase activity, and quercetin (IC50 value was 29.47 ± 3.36 μM) inhibited the activity more effectively than Q3G. We further demonstrated that ESH, Q3G, quercetin, I3G, and isorhamnetin promote GSIS in INS-1 pancreatic β-cells without inducing cytotoxicity. Among them, I3G was the most effective in enhancing GSIS. I3G enhanced the phosphorylation of total extracellular signal-regulated kinase (ERK), insulin receptor substrate-2 (IRS-2), phosphatidylinositol 3-kinase (PI3K), Akt, and activated pancreatic and duodenal homeobox-1 (PDX-1), which are associated with insulin secretion and β-cell function. As components of ESH, Q3G has the potential to regulate blood glucose by inhibiting α-glucosidase activity, and I3G enhances the insulin secretion, but its bioavailability should be considered in determining biological importance.

scholarly journals Ontology of the apelinergic system in mouse pancreas during pregnancy and relationship with β-cell mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brenda Strutt ◽  
Sandra Szlapinski ◽  
Thineesha Gnaneswaran ◽  
Sarah Donegan ◽  
Jessica Hill ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Insulin Secretion ◽  
Glucose Transporter ◽  
Cell Mass ◽  
Elevated Serum ◽  
Pancreatic Β Cell ◽  
Β Cells ◽  
Β Cell ◽  
Glucose Transporter 2 ◽  
Glucose Stimulated Insulin Secretion

AbstractThe apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9–12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.

scholarly journals The Laminin-Induced Acrosome Reaction in Human Sperm Is Mediated by Src Kinases and the Proteasome1

2011 ◽  
Vol 85 (2) ◽  
pp. 357-366 ◽  
Author(s):  
Silvia Tapia ◽  
Marcelo Rojas ◽  
Patricio Morales ◽  
Marco A. Ramirez ◽  
Emilce S. Diaz
Keyword(s):  
Acrosome Reaction ◽  
Human Sperm ◽  
Src Kinases
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