Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells
Activation of pituitary angiotensin (ANG II) type 1 receptors (AT1) mobilizes intracellular Ca2+, resulting in increased prolactin secretion. We first assessed desensitization of AT1 receptors by testing ANG II-induced intracellular Ca2+ concentration ([Ca2+]i) response in rat anterior pituitary cel...
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todo:paper_01931849_v280_n343-3_pE462_Iglesias2023-10-03T15:09:13Z Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells Iglesias, A.G. Suärez, C. Feierstein, C. Díaz-Torga, G. Becu-Villalobos, D. Becü-Villalobos, D. Angiotensin type 1 receptor Calcium Homologous desensitization Protein kinase C Thyrotropin-releasing hormone angiotensin angiotensin 1 receptor calcium ion inositol trisphosphate ionomycin prolactin protein kinase C protirelin animal cell animal experiment article calcium cell level calcium mobilization concentration response controlled study desensitization enzyme activation female hypophysis cell nonhuman priority journal prolactin release Angiotensin II Animals Calcium Cells, Cultured Drug Tolerance Female Inositol 1,4,5-Trisphosphate Ionomycin Pituitary Gland, Anterior Prolactin Protein Kinase C Rats Rats, Sprague-Dawley Receptor, Angiotensin, Type 1 Receptor, Angiotensin, Type 2 Receptors, Angiotensin Tetradecanoylphorbol Acetate Thyrotropin-Releasing Hormone Activation of pituitary angiotensin (ANG II) type 1 receptors (AT1) mobilizes intracellular Ca2+, resulting in increased prolactin secretion. We first assessed desensitization of AT1 receptors by testing ANG II-induced intracellular Ca2+ concentration ([Ca2+]i) response in rat anterior pituitary cells. A period as short as 1 min with 10-7 M ANG II was effective in producing desensitization (remaining response was 66.8 ± 2.1% of nondesensitized cells). Desensitization was a concentration-related event (EC50: 1.1 nM). Although partial recovery was obtained 15 min after removal of ANG II, full response could not be achieved even after 4 h (77.6 ± 2.4%). Experiments with 5 × 10-7 M ionomycin indicated that intracellular Ca2+ stores of desensitized cells had already recovered when desensitization was still significant. The thyrotropin-releasing hormone (TRH)-induced intracellular Ca2+ peak was attenuated in the ANG II-pretreated group. ANG II pretreatment also desensitized ANG II- and TRH-induced inositol phosphate generation (72.8 ± 3.5 and 69.6 ± 6.1%, respectively, for inositol triphosphate) and prolactin secretion (53.4 ± 2.3 and 65.1 ± 7.2%), effects independent of PKC activation. We conclude that, in pituitary cells, inositol triphosphate formation, [Ca2+]i mobilization, and prolactin release in response to ANG II undergo rapid, long-lasting, homologous and heterologous desensitization. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01931849_v280_n343-3_pE462_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 |
Angiotensin type 1 receptor Calcium Homologous desensitization Protein kinase C Thyrotropin-releasing hormone angiotensin angiotensin 1 receptor calcium ion inositol trisphosphate ionomycin prolactin protein kinase C protirelin animal cell animal experiment article calcium cell level calcium mobilization concentration response controlled study desensitization enzyme activation female hypophysis cell nonhuman priority journal prolactin release Angiotensin II Animals Calcium Cells, Cultured Drug Tolerance Female Inositol 1,4,5-Trisphosphate Ionomycin Pituitary Gland, Anterior Prolactin Protein Kinase C Rats Rats, Sprague-Dawley Receptor, Angiotensin, Type 1 Receptor, Angiotensin, Type 2 Receptors, Angiotensin Tetradecanoylphorbol Acetate Thyrotropin-Releasing Hormone |
spellingShingle |
Angiotensin type 1 receptor Calcium Homologous desensitization Protein kinase C Thyrotropin-releasing hormone angiotensin angiotensin 1 receptor calcium ion inositol trisphosphate ionomycin prolactin protein kinase C protirelin animal cell animal experiment article calcium cell level calcium mobilization concentration response controlled study desensitization enzyme activation female hypophysis cell nonhuman priority journal prolactin release Angiotensin II Animals Calcium Cells, Cultured Drug Tolerance Female Inositol 1,4,5-Trisphosphate Ionomycin Pituitary Gland, Anterior Prolactin Protein Kinase C Rats Rats, Sprague-Dawley Receptor, Angiotensin, Type 1 Receptor, Angiotensin, Type 2 Receptors, Angiotensin Tetradecanoylphorbol Acetate Thyrotropin-Releasing Hormone Iglesias, A.G. Suärez, C. Feierstein, C. Díaz-Torga, G. Becu-Villalobos, D. Becü-Villalobos, D. Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
topic_facet |
Angiotensin type 1 receptor Calcium Homologous desensitization Protein kinase C Thyrotropin-releasing hormone angiotensin angiotensin 1 receptor calcium ion inositol trisphosphate ionomycin prolactin protein kinase C protirelin animal cell animal experiment article calcium cell level calcium mobilization concentration response controlled study desensitization enzyme activation female hypophysis cell nonhuman priority journal prolactin release Angiotensin II Animals Calcium Cells, Cultured Drug Tolerance Female Inositol 1,4,5-Trisphosphate Ionomycin Pituitary Gland, Anterior Prolactin Protein Kinase C Rats Rats, Sprague-Dawley Receptor, Angiotensin, Type 1 Receptor, Angiotensin, Type 2 Receptors, Angiotensin Tetradecanoylphorbol Acetate Thyrotropin-Releasing Hormone |
description |
Activation of pituitary angiotensin (ANG II) type 1 receptors (AT1) mobilizes intracellular Ca2+, resulting in increased prolactin secretion. We first assessed desensitization of AT1 receptors by testing ANG II-induced intracellular Ca2+ concentration ([Ca2+]i) response in rat anterior pituitary cells. A period as short as 1 min with 10-7 M ANG II was effective in producing desensitization (remaining response was 66.8 ± 2.1% of nondesensitized cells). Desensitization was a concentration-related event (EC50: 1.1 nM). Although partial recovery was obtained 15 min after removal of ANG II, full response could not be achieved even after 4 h (77.6 ± 2.4%). Experiments with 5 × 10-7 M ionomycin indicated that intracellular Ca2+ stores of desensitized cells had already recovered when desensitization was still significant. The thyrotropin-releasing hormone (TRH)-induced intracellular Ca2+ peak was attenuated in the ANG II-pretreated group. ANG II pretreatment also desensitized ANG II- and TRH-induced inositol phosphate generation (72.8 ± 3.5 and 69.6 ± 6.1%, respectively, for inositol triphosphate) and prolactin secretion (53.4 ± 2.3 and 65.1 ± 7.2%), effects independent of PKC activation. We conclude that, in pituitary cells, inositol triphosphate formation, [Ca2+]i mobilization, and prolactin release in response to ANG II undergo rapid, long-lasting, homologous and heterologous desensitization. |
format |
JOUR |
author |
Iglesias, A.G. Suärez, C. Feierstein, C. Díaz-Torga, G. Becu-Villalobos, D. Becü-Villalobos, D. |
author_facet |
Iglesias, A.G. Suärez, C. Feierstein, C. Díaz-Torga, G. Becu-Villalobos, D. Becü-Villalobos, D. |
author_sort |
Iglesias, A.G. |
title |
Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
title_short |
Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
title_full |
Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
title_fullStr |
Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
title_full_unstemmed |
Desensitization of angiotensin II: Effect on [Ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
title_sort |
desensitization of angiotensin ii: effect on [ca2+]i, inositol triphosphate, and prolactin in pituitary cells |
url |
http://hdl.handle.net/20.500.12110/paper_01931849_v280_n343-3_pE462_Iglesias |
work_keys_str_mv |
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1807322758990790656 |