Measurement of insulin secretion from single pancreatic β cells using a reverse haemolytic plaque assay

1995 ◽  
Vol 23 (2) ◽  
pp. 218S-218S
Author(s):  
H. RATCLIFF ◽  
P.M. JONES
2005 ◽  
Vol 289 (3) ◽  
pp. E439-E445 ◽  
Author(s):  
R. Cruz-Cruz ◽  
A. Salgado ◽  
C. Sánchez-Soto ◽  
L. Vaca ◽  
M. Hiriart

Glucose-induced insulin secretion by pancreatic β-cells depends on membrane depolarization and [Ca2+]i increase. We correlated voltage- and current-clamp recordings, [Ca2+]i measurements, and insulin reverse hemolytic plaque assay to analyze the activity of a thapsigargin-sensitive cationic channel that can be important for membrane depolarization in single rat pancreatic β-cells. We demonstrate the presence of a thapsigargin-sensitive cationic current, which is mainly carried by Na+. Moreover, in basal glucose concentration (5.6 mM), thapsigargin depolarizes the plasma membrane, producing electrical activity and increasing [Ca2+]i. The latter is prevented by nifedipine, indicating that Ca2+ enters the cell through L-type Ca2+ channels, which are activated by membrane depolarization. Thapsigargin also increased insulin secretion by increasing the percentage of cells secreting insulin and amplifying hormone secretion by individual β-cells. Nifedipine blocked the increase completely in 5.6 mM glucose and partially in 15.6 mM glucose. We conclude that thapsigargin potentiates a cationic current that depolarizes the cell membrane. This, in turn, increases Ca2+ entry through L-type Ca2+ channels promoting insulin secretion.


Endocrinology ◽  
2012 ◽  
Vol 153 (11) ◽  
pp. 5180-5187 ◽  
Author(s):  
Hitoshi Katsuta ◽  
Cristina Aguayo-Mazzucato ◽  
Rimiko Katsuta ◽  
Tomoyuki Akashi ◽  
Jennifer Hollister-Lock ◽  
...  

Abstract There is growing information about the heterogeneity of pancreatic β-cells and how it relates to insulin secretion. This study used the approach of flow cytometry to sort and analyze β-cells from transgenic mice expressing green fluorescent protein (GFP) under the control of the mouse insulin I gene promoter. Three populations of β-cells with differing GFP brightness could be identified, which were classified as GFP-low, GFP-medium, and GFP-bright. The GFP-medium population comprised about 70% of the total. The GFP-low population had less insulin secretion as determined by the reverse hemolytic plaque assay and reduced insulin gene expression. Additionally, all three subpopulations of β-cells were found in mice of varying ages (embryonic d 15.5 and postnatal wk 1–9). The three populations from the youngest had larger cells (forward scatter) and less granularity (side scatter) than those from the adults. This approach opens up new ways to advance knowledge about β-cell heterogeneity.


2020 ◽  
Vol 33 (5) ◽  
pp. 671-674
Author(s):  
Tashunka Taylor-Miller ◽  
Jayne Houghton ◽  
Paul Munyard ◽  
Yadlapalli Kumar ◽  
Clinda Puvirajasinghe ◽  
...  

AbstractBackgroundCongenital hyperinsulinism (CHI), a condition characterized by dysregulation of insulin secretion from the pancreatic β cells, remains one of the most common causes of hyperinsulinemic, hypoketotic hypoglycemia in the newborn period. Mutations in ABCC8 and KCNJ11 constitute the majority of genetic forms of CHI.Case presentationA term macrosomic male baby, birth weight 4.81 kg, born to non-consanguineous parents, presented on day 1 of life with severe and persistent hypoglycemia. The biochemical investigations confirmed a diagnosis of CHI. Diazoxide was started and progressively increased to 15 mg/kg/day to maintain normoglycemia. Sequence analysis identified compound heterozygous mutations in ABCC8 c.4076C>T and c.4119+1G>A inherited from the unaffected father and mother, respectively. The mutations are reported pathogenic. The patient is currently 7 months old with a sustained response to diazoxide.ConclusionsBiallelic ABCC8 mutations are known to result in severe, diffuse, diazoxide-unresponsive hypoglycemia. We report a rare patient with CHI due to compound heterozygous mutations in ABCC8 responsive to diazoxide.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nana Kobayashi ◽  
Shogo Okazaki ◽  
Oltea Sampetrean ◽  
Junichiro Irie ◽  
Hiroshi Itoh ◽  
...  

2020 ◽  
Vol 11 ◽  
Author(s):  
Mengmeng Liu ◽  
Lele Ren ◽  
Xiangqin Zhong ◽  
Yaqin Ding ◽  
Tao Liu ◽  
...  

2016 ◽  
Vol 14 (11) ◽  
pp. 823-834 ◽  
Author(s):  
Xiao-Meng WAN ◽  
Mu ZHANG ◽  
Pei ZHANG ◽  
Zhi-Shen XIE ◽  
Feng-Guo XU ◽  
...  

2012 ◽  
Vol 287 (36) ◽  
pp. 30368-30375 ◽  
Author(s):  
Xin-Ya Chen ◽  
Xiu-Ting Gu ◽  
Hexige Saiyin ◽  
Bo Wan ◽  
Yu-Jing Zhang ◽  
...  

2011 ◽  
Vol 120 (9) ◽  
pp. 403-413 ◽  
Author(s):  
Mark A. Russell ◽  
Noel G. Morgan

Common polymorphisms within the FTO (fat mass and obesity-associated) gene correlate with increased BMI (body mass index) and a rising risk of Type 2 diabetes. FTO is highly expressed in the brain but has also been detected in peripheral tissues, including the endocrine pancreas, although its function there is unclear. The aim of the present study was to investigate the role of FTO protein in pancreatic β-cells using a conditional expression system developed in INS-1 cells. INS-1 cells were stably transfected with FTO–HA (haemagluttinin) incorporated under the control of a tetracycline-inducible promoter. Induction of FTO protein resulted in localization of the tagged protein to the nucleus. The level of FTO–HA protein achieved in transfected cells was tightly regulated, and experiments with selective inhibitors revealed that FTO–HA is rapidly degraded via the ubiquitin/proteasome pathway. The nuclear localization was not altered by proteasome inhibitors, although following treatment with PYR-41, an inhibitor of ubiquitination, some of the protein adopted a perinuclear localization. Unexpectedly, modestly increased expression of FTO–HA selectively enhanced the first phase of insulin secretion when INS-1 monolayers or pseudoislets were stimulated with 20 mM glucose, whereas the second phase remained unchanged. The mechanism responsible for the potentiation of glucose-induced insulin secretion is unclear; however, further experiments revealed that it did not involve an increase in insulin biosynthesis or any changes in STAT3 (signal transducer and activator of transcription 3) expression. Taken together, these results suggest that the FTO protein may play a hitherto unrecognized role in the control of first-phase insulin secretion in pancreatic β-cells.


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