Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells

In rat pituitary cells from estrogen-induced hyperplasia, angiotensin II (ANG II) does not evoke a clear spike elevation of intracellular Ca2+ concentration ([Ca2+](i)) but induces a plateau increase. The present work was undertaken to establish whether this difference was related to a differential...

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Autores principales:	Iglesias, A.G., Diaz-Torga, G., Lux-Lantos, V., Libertun, C., Becu-Villalobos, D.
Formato:	JOUR
Materias:	Estrogen Inositol trisphosphate Nifedipine Thapsigargin angiotensin calcium channel calcium ion estrogen inositol trisphosphate nifedipine thapsigargin animal cell article calcium cell level calcium homeostasis calcium mobilization calcium transport cell hyperplasia controlled study estrus cycle female hypophysis cell nonhuman phosphoinositide metabolism priority journal rat Angiotensin II Animals Calcium Calcium Channel Blockers Calcium Channels, L-Type Female Hyperplasia Inositol 1,4,5-Trisphosphate Intracellular Membranes Pituitary Gland Potassium Rats Rats, Sprague-Dawley Reference Values
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_01931849_v277_n340-3_pE455_Iglesias
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	todo:paper_01931849_v277_n340-3_pE455_Iglesias2023-10-03T15:09:13Z Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells Iglesias, A.G. Diaz-Torga, G. Lux-Lantos, V. Libertun, C. Becu-Villalobos, D. Estrogen Inositol trisphosphate Nifedipine Thapsigargin angiotensin calcium channel calcium ion estrogen inositol trisphosphate nifedipine thapsigargin animal cell article calcium cell level calcium homeostasis calcium mobilization calcium transport cell hyperplasia controlled study estrus cycle female hypophysis cell nonhuman phosphoinositide metabolism priority journal rat Angiotensin II Animals Calcium Calcium Channel Blockers Calcium Channels, L-Type Female Hyperplasia Inositol 1,4,5-Trisphosphate Intracellular Membranes Pituitary Gland Potassium Rats Rats, Sprague-Dawley Reference Values Thapsigargin In rat pituitary cells from estrogen-induced hyperplasia, angiotensin II (ANG II) does not evoke a clear spike elevation of intracellular Ca2+ concentration ([Ca2+](i)) but induces a plateau increase. The present work was undertaken to establish whether this difference was related to a differential participation of intracellular and/or plasma membrane Ca2+ channels. We first tested the effect of 10 nM ANG II on [Ca2+](i) in the absence of extracellular Ca2+ in cells depolarized with 25 mM K+ or in the presence of blockers of L-type voltage-sensitive Ca2+ channels (VSCC). These treatments did not alter spike elevation in [Ca2+](i) in controls but reduced plateau levels in hyperplastic cells. Intracellular Ca2+ stores were similar in both groups, as assessed by thapsigargin treatment, but this drug abolished spike increase in controls and scarcely modified plateau levels in hyperplastic cells. Finally, inositol trisphosphate (InsP3) production in response to ANG II was significantly higher in control cells. We conclude that the observed plateau rise in hyperplastic cells results mainly from Ca2+ influx through VSCC. In contrast, in control cells, the ANG II-induced spike increase in [Ca2+](i) results from mobilization of Ca2+ from thapsigargin-sensitive internal channels, activated by higher inositol 1,4,5-trisphosphate generation. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01931849_v277_n340-3_pE455_Iglesias
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Estrogen Inositol trisphosphate Nifedipine Thapsigargin angiotensin calcium channel calcium ion estrogen inositol trisphosphate nifedipine thapsigargin animal cell article calcium cell level calcium homeostasis calcium mobilization calcium transport cell hyperplasia controlled study estrus cycle female hypophysis cell nonhuman phosphoinositide metabolism priority journal rat Angiotensin II Animals Calcium Calcium Channel Blockers Calcium Channels, L-Type Female Hyperplasia Inositol 1,4,5-Trisphosphate Intracellular Membranes Pituitary Gland Potassium Rats Rats, Sprague-Dawley Reference Values Thapsigargin
spellingShingle	Estrogen Inositol trisphosphate Nifedipine Thapsigargin angiotensin calcium channel calcium ion estrogen inositol trisphosphate nifedipine thapsigargin animal cell article calcium cell level calcium homeostasis calcium mobilization calcium transport cell hyperplasia controlled study estrus cycle female hypophysis cell nonhuman phosphoinositide metabolism priority journal rat Angiotensin II Animals Calcium Calcium Channel Blockers Calcium Channels, L-Type Female Hyperplasia Inositol 1,4,5-Trisphosphate Intracellular Membranes Pituitary Gland Potassium Rats Rats, Sprague-Dawley Reference Values Thapsigargin Iglesias, A.G. Diaz-Torga, G. Lux-Lantos, V. Libertun, C. Becu-Villalobos, D. Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
topic_facet	Estrogen Inositol trisphosphate Nifedipine Thapsigargin angiotensin calcium channel calcium ion estrogen inositol trisphosphate nifedipine thapsigargin animal cell article calcium cell level calcium homeostasis calcium mobilization calcium transport cell hyperplasia controlled study estrus cycle female hypophysis cell nonhuman phosphoinositide metabolism priority journal rat Angiotensin II Animals Calcium Calcium Channel Blockers Calcium Channels, L-Type Female Hyperplasia Inositol 1,4,5-Trisphosphate Intracellular Membranes Pituitary Gland Potassium Rats Rats, Sprague-Dawley Reference Values Thapsigargin
description	In rat pituitary cells from estrogen-induced hyperplasia, angiotensin II (ANG II) does not evoke a clear spike elevation of intracellular Ca2+ concentration ([Ca2+](i)) but induces a plateau increase. The present work was undertaken to establish whether this difference was related to a differential participation of intracellular and/or plasma membrane Ca2+ channels. We first tested the effect of 10 nM ANG II on [Ca2+](i) in the absence of extracellular Ca2+ in cells depolarized with 25 mM K+ or in the presence of blockers of L-type voltage-sensitive Ca2+ channels (VSCC). These treatments did not alter spike elevation in [Ca2+](i) in controls but reduced plateau levels in hyperplastic cells. Intracellular Ca2+ stores were similar in both groups, as assessed by thapsigargin treatment, but this drug abolished spike increase in controls and scarcely modified plateau levels in hyperplastic cells. Finally, inositol trisphosphate (InsP3) production in response to ANG II was significantly higher in control cells. We conclude that the observed plateau rise in hyperplastic cells results mainly from Ca2+ influx through VSCC. In contrast, in control cells, the ANG II-induced spike increase in [Ca2+](i) results from mobilization of Ca2+ from thapsigargin-sensitive internal channels, activated by higher inositol 1,4,5-trisphosphate generation.
format	JOUR
author	Iglesias, A.G. Diaz-Torga, G. Lux-Lantos, V. Libertun, C. Becu-Villalobos, D.
author_facet	Iglesias, A.G. Diaz-Torga, G. Lux-Lantos, V. Libertun, C. Becu-Villalobos, D.
author_sort	Iglesias, A.G.
title	Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
title_short	Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
title_full	Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
title_fullStr	Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
title_full_unstemmed	Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells
title_sort	calcium influx and intracellular stores in angiotensin ii stimulation of normal and hyperplastic pituitary cells
url	http://hdl.handle.net/20.500.12110/paper_01931849_v277_n340-3_pE455_Iglesias
work_keys_str_mv	AT iglesiasag calciuminfluxandintracellularstoresinangiotensiniistimulationofnormalandhyperplasticpituitarycells AT diaztorgag calciuminfluxandintracellularstoresinangiotensiniistimulationofnormalandhyperplasticpituitarycells AT luxlantosv calciuminfluxandintracellularstoresinangiotensiniistimulationofnormalandhyperplasticpituitarycells AT libertunc calciuminfluxandintracellularstoresinangiotensiniistimulationofnormalandhyperplasticpituitarycells AT becuvillalobosd calciuminfluxandintracellularstoresinangiotensiniistimulationofnormalandhyperplasticpituitarycells
_version_	1807317702041141248

Calcium influx and intracellular stores in angiotensin II stimulation of normal and hyperplastic pituitary cells

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