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

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 glucos...

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Autores principales:	Borelli, María Inés, Rubio, Modesto Carlos, García, María Elisa, Flores, Luis Emilio, Gagliardino, Juan José
Formato:	Articulo
Lenguaje:	Español
Publicado:	2003
Materias:	Ciencias Médicas carbohydrate catecholamine glucose insulin enzyme activity hormonal regulation
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/36459 http://www.biomedcentral.com/content/pdf/1472-6823-3-2.pdf
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

id	I19-R120-10915-36459
record_format	dspace
institution	Universidad Nacional de La Plata
institution_str	I-19
repository_str	R-120
collection	SEDICI (UNLP)
language	Español
topic	Ciencias Médicas carbohydrate catecholamine glucose insulin enzyme activity hormonal regulation
spellingShingle	Ciencias Médicas carbohydrate catecholamine glucose insulin enzyme activity hormonal regulation Borelli, María Inés Rubio, Modesto Carlos García, María Elisa Flores, Luis Emilio Gagliardino, Juan José Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
topic_facet	Ciencias Médicas carbohydrate catecholamine glucose insulin enzyme activity hormonal regulation
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.
format	Articulo Articulo
author	Borelli, María Inés Rubio, Modesto Carlos García, María Elisa Flores, Luis Emilio Gagliardino, Juan José
author_facet	Borelli, María Inés Rubio, Modesto Carlos García, María Elisa Flores, Luis Emilio Gagliardino, Juan José
author_sort	Borelli, María Inés
title	Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation
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
publishDate	2003
url	http://sedici.unlp.edu.ar/handle/10915/36459 http://www.biomedcentral.com/content/pdf/1472-6823-3-2.pdf
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Tyrosine hydroxylase activity in the endocrine pancreas: changes induced by short-term dietary manipulation

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