Glucagon levels in normal and diabetic subjects: Use of a specific immunoabsorbent for glucagon radioimmunoassay

Alford, F. P.; Bloom, S R; Nabarro, J. D. N.

doi:10.1007/bf00996319

Cited by 128 publications

(37 citation statements)

References 21 publications

(31 reference statements)

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“…However, the physiological concentration of glucagon released in islet secretions is less than 17 pM, which is lower than the detection limit of the sensor, and its influence was considered insignificant. [49][50] The concentration levels of amylin and somatostatin in the islet secretion are also very small, about 1/100 and 1/25 of the insulin concentration, respectively. [51][52] And, pancreatic polypeptide does not show the Raman peak at 1002 cm -1 from phenylalanine.…”

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confidence: 99%

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

Cho¹,

Kumar²,

Yang³

et al. 2018

ACS Sens.

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Label-free optical detection of insulin would allow in vitro assessment of pancreatic cell functions in their natural state and expedite diabetes-related clinical research and treatment, however no existing method has met these criteria at physiological concentrations. Using spatially-uniform 3D gold-nanoparticle sensors, we have demonstrated surface-enhanced Raman sensing of insulin in the secretions from human pancreatic islets under low and high glucose environments without the use of labels such as antibodies or aptamers. Label-free measurements of the islet secretions showed excellent correlation among the ambient glucose levels, secreted insulin concentrations, and measured Raman-emission intensities. When excited at 785 nm, plasmonic hotspots of the densely-arranged 3D gold-nanoparticle pillars as well as strong interaction between sulphide linkages of the insulin molecules and the gold nanoparticles produced highly sensitive and reliable insulin measurements down to 100 pM. The sensors exhibited a dynamic range of 100 pM to 50 nM with an estimated detection limit of 35 pM, which covers the reported concentration range of insulin observed in pancreatic cell secretions.The sensitivity of this approach is approximately four orders of magnitude greater than previously reported results using label-free optical approaches, and it is much more costeffective than immunoassay-based insulin detection widely used in clinics and laboratories. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 Hormones are chemical messengers that control a wide variety of functions in the human body. Maintaining adequate hormone levels is extremely important for human health and disruption to these levels can result in life-debilitating conditions. Simple and easy measurements of hormonal secretions ex vivo or in vivo are essential for implementing next generation biosensors, allowing convenient monitoring of health and early disease detection.One of the most prevalent diseases resulting from hormonal dysfunction is diabetes, which arises from a disruption in the release of insulin in the body. 1-2 Insulin is a peptide hormone which is secreted by beta cells, one of five primary cell-types which populate pancreatic cellular clusters known as islets. The concentration of insulin secreted from beta cells in plasma has been reported to vary between 100 pM (fasting) and 2 nM (about 1 hour after glucose intake) in non-diabetic individuals. [3][4] In diabetic individuals, functional damage to the beta cells reduces or inhibits their ability to release insulin. One of the leading methodologies for treatment of type-1 diabetes is pancreatic islet transplantation, where healthy islets harvested from deceased donors are transplanted into diabetic patients. [5][6] Since the number of donors is limited, methodologies that can improve the efficiency and succe...

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confidence: 99%

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

Cho¹,

Kumar²,

Yang³

et al. 2018

ACS Sens.

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“…Glucagon was measured by radioimmunoassay (Alford et al, 1977), cAMP was assayed by saturation analysis (Brown et al, 1971) and noradrenaline and adrenaline by COMT radioenzymatic assay (Brown et al, 1981). Blood glucose was measured by a glucose oxidase method using an auto-analyser.…”

Section: Methodsmentioning

confidence: 99%

The effect of selective and non‐selective beta‐adrenoceptor blockade, and of naloxone infusion, on the hormonal mechanisms of recovery from insulin‐induced hypoglycaemia in man.

Armitstead¹,

Lightman²,

Brown³

et al. 1983

Brit J Clinical Pharma

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The rise in plasma adenosine-3',5'-monophosphate occurring in response to insulin induced hypoglycaemia in normal human subjects, was abolished by non-selective ,3-adrenoceptor blockade but unaffected by selective (31-adrenoceptor blockade. This implies that the rise is secondary to /2-adrenoceptor stimulation. The abolition of this rise by non-selective f3-adrenoceptor blockade had no pronounced effect on the recovery from hypoglycaemia. Endogenous opiate receptor blockade with naloxone had no significant effect on the recovery from insulin induced hypoglycaemia, or the hormonal mechanisms involved.

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“…Further studies are needed to determine whether glucagon [20][21][22][23][24][25][26][27][28][29] bonds [33] . However other studies have suggested that IDE cleaves at Arg 17 -Arg 18 bonds with the formation of glucagon [18][19][20][21][22][23][24][25][26][27][28][29] , which may then be converted into glucagon [19][20][21][22][23][24][25][26][27][28][29] by an unidentified aminopeptidase like enzyme [34] . It is possible that such residual hepatocyte enzymes are present in plasma leading to the formation of glucagon [19][20][21][22][23][24][25][26][27][28][29] , and perhaps lead to the formation of glucagon [20]…”

Section: Figurementioning

confidence: 99%

“…Glucagon [1][2][3][4][5][6][7][8][9][10][11][12][13] and glucagon [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] , and the minor metabolites glucagon [1][2][3][4][5][6][7][8][9][10] , glucagon [14][15][16][17][18][19][20][21][22][23][24][25] and glucagon [23][24]…”

Section: Introductionunclassified

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Identification of plasma protease derived metabolites of glucagon and their formation under typical laboratory sample handling conditions

Howard

Kay²,

Tan

et al. 2014

Rapid Comm Mass Spectrometry

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RATIONALE Glucagon modulates glucose production, and it is also a biomarker for several pathologies. It is known to be unstable in human plasma, and consequently stabilisers are often added to samples, although these are not particularly effective. Despite this, there have not been any studies to identify in vitro plasma protease derived metabolites; such a study is described here. Knowledge of metabolism should allow the development of more effective sample stabilisation strategies. METHODS Several novel metabolites resulting from the incubation of glucagon in human plasma were identified using high‐resolution mass spectrometry with positive electrospray ionisation. Tandem mass spectrometric (MS/MS) scans were acquired for additional confirmation using a QTRAP. Separation was performed using reversed‐phase ultra‐high‐performance liquid chromatography. The formation of these metabolites was investigated during a time‐course experiment and under specific stress conditions representative of typical laboratory handling conditions. Clinical samples were also screened for metabolites. RESULTS Glucagon3‐29 and [pGlu]3glucagon3‐29 were the major metabolites detected, both of which were also present in clinical samples. We also identified two oxidised forms of [pGlu]3glucagon3‐29 as well as glucagon19‐29, or 'miniglucagon', along with the novel metabolites glucagon20‐29 and glucagon21‐29. The relative levels of these metabolites varied throughout the time‐course experiment, and under the application of the different sample handling conditions. Aprotinin stabilisation of samples had negligible effect on metabolite formation. CONCLUSIONS Novel plasma protease metabolites of glucagon have been confirmed, and their formation characterised over a time‐course experiment and under typical laboratory handling conditions. These metabolites could be monitored to assess the effectiveness of new sample stabilisation strategies, and further investigations into their formation could suggest specific enzyme inhibitors to use to increase sample stability. In addition the potential of the metabolites to affect immunochemistry‐based assays as a result of cross‐reactivity could be investigated. Copyright © 2014 John Wiley & Sons, Ltd.

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Glucagon levels in normal and diabetic subjects: Use of a specific immunoabsorbent for glucagon radioimmunoassay

Cited by 128 publications

References 21 publications

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

Surface-Enhanced Raman Spectroscopy-Based Label-Free Insulin Detection at Physiological Concentrations for Analysis of Islet Performance

The effect of selective and non‐selective beta‐adrenoceptor blockade, and of naloxone infusion, on the hormonal mechanisms of recovery from insulin‐induced hypoglycaemia in man.

Identification of plasma protease derived metabolites of glucagon and their formation under typical laboratory sample handling conditions

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