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A role for calmodulin in the regulation of steroidogenesis

Two approaches were used to study the possible role of calmodulin in the regulation of steroid synthesis by mouse adrenal tumor cells: trifluoperazine was used as an inhibitor of calmodulin and liposomes were used to deliver calmodulin into the cells. Trifluoperazine inhibits three steroidogenic res...

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Detalles Bibliográficos
Autores principales: Hall, PF, Osawa, S, Thomasson, CL
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1981
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2111860/
https://www.ncbi.nlm.nih.gov/pubmed/6270154
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author Hall, PF
Osawa, S
Thomasson, CL
author_facet Hall, PF
Osawa, S
Thomasson, CL
author_sort Hall, PF
collection PubMed
description Two approaches were used to study the possible role of calmodulin in the regulation of steroid synthesis by mouse adrenal tumor cells: trifluoperazine was used as an inhibitor of calmodulin and liposomes were used to deliver calmodulin into the cells. Trifluoperazine inhibits three steroidogenic responses to both ACTH and dibutyryl cyclic AMP: (a) increase in steroid production, (b) increased transport of cholesterol to mitochondria, and (c) increased side-chain cleavage by mitochondria isolated from cells incubated with ACTH or dibutyryl cyclic AMP. When calmodulin is introduced into the cells via liposomes, steroid synthesis is slightly stimulated. When calmodulin extensively dialyzed against EGTA, this stimulation is abolished. Ca(2+) introduced via liposomes was also without effect. However, when both calmodulin and Ca(2+) are introduced via liposomes (either in separate liposomes or in the same liposomes), steroid synthesis is stimulated. This stimulation does not occur when either anticalmodulin antibodies or EGTA is also present in the liposomes or when trifluoperazine is present in the incubation medium. Calmodulin and Ca(2+) presented together in liposomes to the cells stimulate transport of cholesterol to mitochondria, and side-chain cleavage activity is greater in mitochondria isolated from cells previously fused with liposomes containing calmodulin and Ca(2+) than in mitochondria from cells fused with liposomes containing buffer only. These observations suggest that calmodulin may be involved in regulating the transport of cholesterol to mitochondria, a process which is stimulated by ACTH and dibutyryl cyclic AMP and which may account, at least in part, for the increase in steroid synthesis produced by these agents.
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spelling pubmed-21118602008-05-01 A role for calmodulin in the regulation of steroidogenesis Hall, PF Osawa, S Thomasson, CL J Cell Biol Articles Two approaches were used to study the possible role of calmodulin in the regulation of steroid synthesis by mouse adrenal tumor cells: trifluoperazine was used as an inhibitor of calmodulin and liposomes were used to deliver calmodulin into the cells. Trifluoperazine inhibits three steroidogenic responses to both ACTH and dibutyryl cyclic AMP: (a) increase in steroid production, (b) increased transport of cholesterol to mitochondria, and (c) increased side-chain cleavage by mitochondria isolated from cells incubated with ACTH or dibutyryl cyclic AMP. When calmodulin is introduced into the cells via liposomes, steroid synthesis is slightly stimulated. When calmodulin extensively dialyzed against EGTA, this stimulation is abolished. Ca(2+) introduced via liposomes was also without effect. However, when both calmodulin and Ca(2+) are introduced via liposomes (either in separate liposomes or in the same liposomes), steroid synthesis is stimulated. This stimulation does not occur when either anticalmodulin antibodies or EGTA is also present in the liposomes or when trifluoperazine is present in the incubation medium. Calmodulin and Ca(2+) presented together in liposomes to the cells stimulate transport of cholesterol to mitochondria, and side-chain cleavage activity is greater in mitochondria isolated from cells previously fused with liposomes containing calmodulin and Ca(2+) than in mitochondria from cells fused with liposomes containing buffer only. These observations suggest that calmodulin may be involved in regulating the transport of cholesterol to mitochondria, a process which is stimulated by ACTH and dibutyryl cyclic AMP and which may account, at least in part, for the increase in steroid synthesis produced by these agents. The Rockefeller University Press 1981-08-01 /pmc/articles/PMC2111860/ /pubmed/6270154 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Hall, PF
Osawa, S
Thomasson, CL
A role for calmodulin in the regulation of steroidogenesis
title A role for calmodulin in the regulation of steroidogenesis
title_full A role for calmodulin in the regulation of steroidogenesis
title_fullStr A role for calmodulin in the regulation of steroidogenesis
title_full_unstemmed A role for calmodulin in the regulation of steroidogenesis
title_short A role for calmodulin in the regulation of steroidogenesis
title_sort role for calmodulin in the regulation of steroidogenesis
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2111860/
https://www.ncbi.nlm.nih.gov/pubmed/6270154
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