TY - JOUR
T1 - Sulfhydryl reagent-induced insulin release and 45ca++ fluxes in syrian hamster insulinoma cells
AU - Erlichman, Jack
AU - Schubart, Ulrich
AU - Fleischer, Norman
PY - 1979/11
Y1 - 1979/11
N2 - Dispersed single cell suspensions of Syrian hamster insulinoma cells were used to study the effects of a variety of sulfhydryl-binding reagents on insulin release and 45Ca++ flux. Incubation of cells with several organic mercurials resulted in a rapid increase in 45Ca++ uptake as well as increased efflux in cells which had been prelabeled with 45Ca++. Concomitant with increased calcium uptake was a 4 to 5-fold increase in insulin released into the medium. Incubation with alkylating reagents such as iodoacetamide and iV-ethyl maleimide or dithiol reagents such as 5, 5′-dithiobis (2-nitrobenzoic acid) failed to stimulate either45Ca++ flux or insulin release. Elimination of medium calcium or preincubation of cells with iV-ethyl maleimide resulted in approximately 50% inhibition of mercurial-induced insulin release from these cells. 8-(N, N2-diethylamino)Octyl- 3, 4, 5, -trimethoxybenzoate or a-isopropyl-a [(N-methyl-iV-homoveratryl) γ-aminopropyl]3, 4, 5′-trimethoxyphenylacetonitrite hydrochloride, agents which block potassium (40 min) -stimulated calcium flux and insulin release, failed to inhibit mercurialinduced calcium flux or insulin secretion. These results indicate that sulfhydryl-binding reagents, through their interaction with critical thiol groups, promote insulin release in these insulinoma cells by inducing changes in calcium fluxes. It is possible that these thiol groups regulate calcium metabolism and, thus, insulin release under physiological conditions.
AB - Dispersed single cell suspensions of Syrian hamster insulinoma cells were used to study the effects of a variety of sulfhydryl-binding reagents on insulin release and 45Ca++ flux. Incubation of cells with several organic mercurials resulted in a rapid increase in 45Ca++ uptake as well as increased efflux in cells which had been prelabeled with 45Ca++. Concomitant with increased calcium uptake was a 4 to 5-fold increase in insulin released into the medium. Incubation with alkylating reagents such as iodoacetamide and iV-ethyl maleimide or dithiol reagents such as 5, 5′-dithiobis (2-nitrobenzoic acid) failed to stimulate either45Ca++ flux or insulin release. Elimination of medium calcium or preincubation of cells with iV-ethyl maleimide resulted in approximately 50% inhibition of mercurial-induced insulin release from these cells. 8-(N, N2-diethylamino)Octyl- 3, 4, 5, -trimethoxybenzoate or a-isopropyl-a [(N-methyl-iV-homoveratryl) γ-aminopropyl]3, 4, 5′-trimethoxyphenylacetonitrite hydrochloride, agents which block potassium (40 min) -stimulated calcium flux and insulin release, failed to inhibit mercurialinduced calcium flux or insulin secretion. These results indicate that sulfhydryl-binding reagents, through their interaction with critical thiol groups, promote insulin release in these insulinoma cells by inducing changes in calcium fluxes. It is possible that these thiol groups regulate calcium metabolism and, thus, insulin release under physiological conditions.
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U2 - 10.1210/endo-105-5-1183
DO - 10.1210/endo-105-5-1183
M3 - Article
C2 - 226348
AN - SCOPUS:0018566881
SN - 0013-7227
VL - 105
SP - 1183
EP - 1190
JO - Endocrinology
JF - Endocrinology
IS - 5
ER -