Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation

Autores
Borelli, María Inés; Rubio, Modesto Carlos; García, María Elisa; Flores, Luis Emilio; Gagliardino, Juan José
Año de publicación
2003
Idioma
español castellano
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Background: Tyrosine hydroxylase (TH) activity and its possible participation in the control of insulin secretion were studied in pancreatic islets of adult Wistar rats fed a standard commercial diet (SD) or carbohydrates alone (CHD) for one week. TH activity, norepinephrine (NE) content, and glucose-induced insulin secretion were assessed. Blood glucose and insulin levels were measured at the time of sacrifice. Results: CHD rats had significantly higher blood glucose and lower insulin levels than SD rats (114.5 ± 6.7 vs 80.7 ± 7.25 mg/dl, p < 0.001; 20.25 ± 2.45 vs 42.5 ± 4.99 μU/ml, p < 0.01, respectively). Whereas TH activity was significantly higher in CHD isolated islets (600 ± 60 vs 330 ± 40 pmol/mg protein/h; p < 0.001), NE content was significantly lower (18 ± 1 vs 31 ± 5 pmol/mg protein), suggesting that TH activity would be inhibited by the end-products of catecholamines (CAs) biosynthetic pathway. A similar TH activity was found in control and solarectomized rats (330 ± 40 vs 300 ± 80 pmol/mg protein/h), suggesting an endogenous rather than a neural origin of TH activity. CHD islets released significantly less insulin in response to glucose than SD islets (7.4 ± 0.9 vs 11.4 ± 1.1 ng/islet/h; p < 0.02). Conclusions: TH activity is present in islet cells; dietary manipulation simultaneously induces an increase in this activity together with a decrease in glucose-induced insulin secretion in rat islets. TH activity - and the consequent endogenous CAs turnover - would participate in the paracrine control of insulin secretion.
Facultad de Ciencias Médicas
Materia
Ciencias Médicas
carbohydrate
catecholamine
glucose
insulin
enzyme activity
hormonal regulation
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/3.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/36459
Acceder
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oai_identifier_str oai:sedici.unlp.edu.ar:10915/36459
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulationBorelli, María InésRubio, Modesto CarlosGarcía, María ElisaFlores, Luis EmilioGagliardino, Juan JoséCiencias Médicascarbohydratecatecholamineglucoseinsulinenzyme activityhormonal regulationBackground: Tyrosine hydroxylase (TH) activity and its possible participation in the control of insulin secretion were studied in pancreatic islets of adult Wistar rats fed a standard commercial diet (SD) or carbohydrates alone (CHD) for one week. TH activity, norepinephrine (NE) content, and glucose-induced insulin secretion were assessed. Blood glucose and insulin levels were measured at the time of sacrifice. Results: CHD rats had significantly higher blood glucose and lower insulin levels than SD rats (114.5 ± 6.7 vs 80.7 ± 7.25 mg/dl, p < 0.001; 20.25 ± 2.45 vs 42.5 ± 4.99 μU/ml, p < 0.01, respectively). Whereas TH activity was significantly higher in CHD isolated islets (600 ± 60 vs 330 ± 40 pmol/mg protein/h; p < 0.001), NE content was significantly lower (18 ± 1 vs 31 ± 5 pmol/mg protein), suggesting that TH activity would be inhibited by the end-products of catecholamines (CAs) biosynthetic pathway. A similar TH activity was found in control and solarectomized rats (330 ± 40 vs 300 ± 80 pmol/mg protein/h), suggesting an endogenous rather than a neural origin of TH activity. CHD islets released significantly less insulin in response to glucose than SD islets (7.4 ± 0.9 vs 11.4 ± 1.1 ng/islet/h; p < 0.02). Conclusions: TH activity is present in islet cells; dietary manipulation simultaneously induces an increase in this activity together with a decrease in glucose-induced insulin secretion in rat islets. TH activity - and the consequent endogenous CAs turnover - would participate in the paracrine control of insulin secretion.Facultad de Ciencias Médicas2003-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/36459spainfo:eu-repo/semantics/altIdentifier/url/http://www.biomedcentral.com/content/pdf/1472-6823-3-2.pdfinfo:eu-repo/semantics/altIdentifier/issn/1472-6823info:eu-repo/semantics/altIdentifier/doi/10.1186/1472-6823-3-2info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/3.0/Creative Commons Attribution 3.0 Unported (CC BY 3.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T10:57:03Zoai:sedici.unlp.edu.ar:10915/36459Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 10:57:04.08SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
title Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
spellingShingle Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
Borelli, María Inés
Ciencias Médicas
carbohydrate
catecholamine
glucose
insulin
enzyme activity
hormonal regulation
title_short Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
title_full Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
title_fullStr Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
title_full_unstemmed Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
title_sort Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
dc.creator.none.fl_str_mv Borelli, María Inés
Rubio, Modesto Carlos
García, María Elisa
Flores, Luis Emilio
Gagliardino, Juan José
author Borelli, María Inés
author_facet Borelli, María Inés
Rubio, Modesto Carlos
García, María Elisa
Flores, Luis Emilio
Gagliardino, Juan José
author_role author
author2 Rubio, Modesto Carlos
García, María Elisa
Flores, Luis Emilio
Gagliardino, Juan José
author2_role author
author
author
author
dc.subject.none.fl_str_mv Ciencias Médicas
carbohydrate
catecholamine
glucose
insulin
enzyme activity
hormonal regulation
topic Ciencias Médicas
carbohydrate
catecholamine
glucose
insulin
enzyme activity
hormonal regulation
dc.description.none.fl_txt_mv Background: Tyrosine hydroxylase (TH) activity and its possible participation in the control of insulin secretion were studied in pancreatic islets of adult Wistar rats fed a standard commercial diet (SD) or carbohydrates alone (CHD) for one week. TH activity, norepinephrine (NE) content, and glucose-induced insulin secretion were assessed. Blood glucose and insulin levels were measured at the time of sacrifice. Results: CHD rats had significantly higher blood glucose and lower insulin levels than SD rats (114.5 ± 6.7 vs 80.7 ± 7.25 mg/dl, p < 0.001; 20.25 ± 2.45 vs 42.5 ± 4.99 μU/ml, p < 0.01, respectively). Whereas TH activity was significantly higher in CHD isolated islets (600 ± 60 vs 330 ± 40 pmol/mg protein/h; p < 0.001), NE content was significantly lower (18 ± 1 vs 31 ± 5 pmol/mg protein), suggesting that TH activity would be inhibited by the end-products of catecholamines (CAs) biosynthetic pathway. A similar TH activity was found in control and solarectomized rats (330 ± 40 vs 300 ± 80 pmol/mg protein/h), suggesting an endogenous rather than a neural origin of TH activity. CHD islets released significantly less insulin in response to glucose than SD islets (7.4 ± 0.9 vs 11.4 ± 1.1 ng/islet/h; p < 0.02). Conclusions: TH activity is present in islet cells; dietary manipulation simultaneously induces an increase in this activity together with a decrease in glucose-induced insulin secretion in rat islets. TH activity - and the consequent endogenous CAs turnover - would participate in the paracrine control of insulin secretion.
Facultad de Ciencias Médicas
description Background: Tyrosine hydroxylase (TH) activity and its possible participation in the control of insulin secretion were studied in pancreatic islets of adult Wistar rats fed a standard commercial diet (SD) or carbohydrates alone (CHD) for one week. TH activity, norepinephrine (NE) content, and glucose-induced insulin secretion were assessed. Blood glucose and insulin levels were measured at the time of sacrifice. Results: CHD rats had significantly higher blood glucose and lower insulin levels than SD rats (114.5 ± 6.7 vs 80.7 ± 7.25 mg/dl, p < 0.001; 20.25 ± 2.45 vs 42.5 ± 4.99 μU/ml, p < 0.01, respectively). Whereas TH activity was significantly higher in CHD isolated islets (600 ± 60 vs 330 ± 40 pmol/mg protein/h; p < 0.001), NE content was significantly lower (18 ± 1 vs 31 ± 5 pmol/mg protein), suggesting that TH activity would be inhibited by the end-products of catecholamines (CAs) biosynthetic pathway. A similar TH activity was found in control and solarectomized rats (330 ± 40 vs 300 ± 80 pmol/mg protein/h), suggesting an endogenous rather than a neural origin of TH activity. CHD islets released significantly less insulin in response to glucose than SD islets (7.4 ± 0.9 vs 11.4 ± 1.1 ng/islet/h; p < 0.02). Conclusions: TH activity is present in islet cells; dietary manipulation simultaneously induces an increase in this activity together with a decrease in glucose-induced insulin secretion in rat islets. TH activity - and the consequent endogenous CAs turnover - would participate in the paracrine control of insulin secretion.
publishDate 2003
dc.date.none.fl_str_mv 2003-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/36459
url http://sedici.unlp.edu.ar/handle/10915/36459
dc.language.none.fl_str_mv spa
language spa
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/http://www.biomedcentral.com/content/pdf/1472-6823-3-2.pdf
info:eu-repo/semantics/altIdentifier/issn/1472-6823
info:eu-repo/semantics/altIdentifier/doi/10.1186/1472-6823-3-2
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/3.0/
Creative Commons Attribution 3.0 Unported (CC BY 3.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/3.0/
Creative Commons Attribution 3.0 Unported (CC BY 3.0)
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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