Fluctuations of calcium, phosphorus, sodium, potassium, and chlorine in single alpha and beta cells during glucose perifusion of rat islets.

Kalkhoff, Ronald K.; Siegesmund, Kenneth A.

doi:10.1172/jci110283

Cited by 23 publications

(19 citation statements)

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“…As (8). These temporal, phasic relationships underscore the importance of cytosolic elevations of Ca++ as second messengers for the insulin secretory process, and, by direct measurement, support conclusions drawn by others utilizing flux measurements of labeled Ca in whole islets exposed to tolbutamide in vitro (2,3,(5)(6)(7).…”

Section: Methodssupporting

confidence: 81%

“…We assume that the content of retained elements in tolbutamide-stimulated beta cells relative to corresponding control cells at any given moment is representative of the in vivo situation, even though precise quantitation is not possible. In support of this second assumption is our previous report of distinctive, sequential changes of these elements in both beta and alpha cells following D-glucose as opposed to D-galactose challenges (8).…”

Section: Introductionmentioning

confidence: 57%

“…Details of our experimental techniques have been published previously in this journal (8). Pancreatic islets from fed, female rats were isolated by a collagenase technique (9).…”

Section: Methodsmentioning

confidence: 99%

“…100 isolated islets were transferred to one of two plastic perifusion chambers containing appropriate filters. They were submerged in a water bath at 37°C and perifusion was carried out according to the method of Lacy et al (10) (8). A thin layer of carbon subsequently was evaporated onto the surface of the filter-containing islets.…”

Section: Methodsmentioning

confidence: 99%

“…A thin layer of carbon subsequently was evaporated onto the surface of the filter-containing islets. SEM utilized a JSM U-3 scanning electron microscope JEOL U.S.A., Peabody, MA at a potential of 25,000 V. Single, unobscured beta cells that were attached to islets were identified by size and shape criteria as previously described (8). After identification, the cell was subjected to EDXA utilizing an attached Nuclear Semiconductor 155e V resolution Si (Li) The earliest event to occur in these studies was an abrupt rise in beta cell Ca in islets perifused with tolbutamide.…”

Section: Methodsmentioning

confidence: 99%

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Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Kalkhoff¹,

Siegesmund²,

Dragen³

1983

J. Clin. Invest.

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A B S T R A C T Fluctuations of calcium, phosphorus, sodium, potassium, and chlorine in beta cells were followed during rat islet perifusion with tolbutamide and related to insulin secretion. In 24 paired experiments two chambers containing 100 islets were perifused with buffered medium containing 4.2 mM glucose alone or with added tolbutamide (200 Ag/ml). Effluent was collected frequently for insulin determinations.At eight different time intervals from 0 to 20 min islets were acutely fixed, prepared for scanning electron microscopy and beta cells in islet tissue were identified. Element content in 480 single cells was measured by energy dispersive x-ray analysis. Tolbutamide elicited typical monophasic insulin release that exceeded control islet secretory rates from 2 to 6 min with a peak value at 3 min. This pattern was preceded by monophasic calcium accumulation in beta cells that abruptly rose 150% above control cells at 1 min and declined to base line by 4 min. The rapid ascent of calcium was associated with significant depressions of sodium and potassium content without alterations of cell phosphorus. Chlorine fell at 2 min and then rose >50% above control cells at 4 min. After 6 min insulin secretion and element content remained near control levels. We conclude that monophasic calcium accumulation in beta cells is the earliest, most predictive event of islet insulin secretion after a tolbutamide stimulus. Oscillations of beta cell sodium and potassium reciprocally relate to calcium, and an elevation of chlorine content is a relatively late phenomenon in the stimulus-secretion coupling process.

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Section: Methodssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 57%

“…Details of our experimental techniques have been published previously in this journal (8). Pancreatic islets from fed, female rats were isolated by a collagenase technique (9).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Kalkhoff¹,

Siegesmund²,

Dragen³

1983

J. Clin. Invest.

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Effects of K⁺‐induced depolarization and purinergic receptor activation on elemental content in insulin‐producing RINm5F‐cells.

Pålsgård

Lindh²,

Juntti‐Berggren³

et al. 1995

Cell Biology International

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X-ray microanalysis was used to detect elemental changes in the insulin-producing tumor cell-line RINm5F. To improve discrimination between mobile ions and ions bound to macromolecules a new approach was employed, consisting of multivariate statistical analysis of correlations between the concentrations of Na, Mg, P, S, Cl, K, and Ca. RINm5F cells, cultured on Formvar-coated titanium grids, were stimulated with high K+ or ATP, that are both known to stimulate insulin release. The buffers used contained Ca2+ or one of the Ca(2+)-analogues Sr2+ and Ba2+, to represent Ca2+ uptake in response to stimulation. After stimulation the cells were shock-frozen and freeze-dried overnight. Incubation for 10-20 seconds in a Ca(2+)-containing buffer did not significantly affect elemental composition, whereas cellular Mg, P and K decreased in a Sr(2+)-containing buffer. Depolarization with high K+ concentration caused an increase in the cellular Na content, both in Ca(2+)- and Sr(2+)-containing buffers, but not in the buffer where Ca2+ had been replaced by Ba2+. X-ray microanalysis is useful for detection of elemental changes subsequent to stimulation of cultured cells. Moreover, multivariate statistical analysis strengthens the idea that stimulation of RINm5F cells causes redistribution of ions possibly due to changes in the state of binding of some elements to cellular proteins.

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Glucose-induced reduction of the sodium content in β-cell-rich pancreatic islets

1986

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The sodium contents of beta-cell-rich pancreatic islets from ob/ob-mice were measured with an integrating flame photometer. After washing to an apparent steady state with different types of ice-cold media, islets incubated in the absence of glucose contained 79-108 mmol sodium kg-1 dry weight. Exposure to glucose resulted in 25% reduction of the islet content of sodium. This effect became manifest in the presence of 5 mM glucose, there being no additional reduction with a further increase of glucose to 20 mM. Depression of Na+ activity may partially explain why glucose, under certain conditions, can lower cytoplasmic Ca2+ and even inhibit insulin release.

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Fluctuations of calcium, phosphorus, sodium, potassium, and chlorine in single alpha and beta cells during glucose perifusion of rat islets.

Cited by 23 publications

References 40 publications

Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Effects of K⁺‐induced depolarization and purinergic receptor activation on elemental content in insulin‐producing RINm5F‐cells.

Glucose-induced reduction of the sodium content in β-cell-rich pancreatic islets

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Fluctuations of calcium, phosphorus, sodium, potassium, and chlorine in single alpha and beta cells during glucose perifusion of rat islets.

Cited by 23 publications

References 40 publications

Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Tolbutamide perifusion of rat islets. Sequential changes in calcium, phosphorus, sodium, potassium, and chlorine in single beta cells.

Effects of K+‐induced depolarization and purinergic receptor activation on elemental content in insulin‐producing RINm5F‐cells.

Glucose-induced reduction of the sodium content in β-cell-rich pancreatic islets

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Effects of K⁺‐induced depolarization and purinergic receptor activation on elemental content in insulin‐producing RINm5F‐cells.