Effects of age on the glucoregulatory response following acute glucoprivation induced by 2-deoxyglucose (2DG) in the Adrenal medulla of Sprague Dawley rats

Nor Azura Muda, Hajira Ramlan, Mohd Hanafi Ahmad Damanhuri

Research output: Contribution to journalArticle

Abstract

OBJECTIVES: Impairment in glucose homeostasis is one of the factors that may alter the feeding drive, hunger and satiety signals, which essential to maintain a sufficient level of energy for daily activities especially among the elderly. Adrenal medulla is one of the important organs that involves in glucose homeostasis through secretion of catecholamines. The catecholamines biosynthesis pathway utilizes various enzymes and protein kinases. The aims of this study are to investigate the effects of age on the biosynthetic pathway of catecholamines in adrenal medulla by determining the level of blood glucose and blood catecholamines, the gene and protein expression of biosynthetic catecholamine enzymes (TH, DBH and PNMT) as well as protein kinase substrates that involved in the phosphorylation of TH in 2DG-induced rats. METHODS: Adrenal medulla from male Sprague Dawley rats at the age of 3-months (n=12) and 24-months (n=12) were further divided into two groups: 1) treatment group with 2DG to create glucoprivation condition and 2) the vehicle group which received normal saline as control. RESULTS: The results showed that the level of glucose, adrenaline and noradrenaline were increased in response to acute glucoprivation conditions in both young and old rats. No age-related differences were found in the basal gene expression of the enzymes that involved in the catecholamines biosynthesis pathway. Interestingly the expressions of TH and DBH protein as well as the level of TH phosphorylation at Ser40, PKA, PKC and ERK1/2 substrates were higher in basal condition of the aged rats. However, contradicted findings were obtained in glucoprivic condition, which the protein expressions of DBH, pERKl/2 and substrates for pPKC were increased in young rats. Only substrate for pCDK was highly expressed in the old rats in the glucoprivic condition, while pPKC and pERKl/2 were decreased significantly. The results demonstrate that adrenal medulla of young and old rats are responsive to glucose deficit and capable to restore the blood glucose level by increasing the levels of blood catecholamines.

Original languageEnglish
Pages (from-to)224-235
Number of pages12
JournalNeuroendocrinology Letters
Volume38
Issue number3
Publication statusPublished - 1 Jan 2017

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Adrenal Medulla
Deoxyglucose
Catecholamines
Sprague Dawley Rats
Glucose
Protein Kinases
Blood Glucose
Homeostasis
Enzymes
Phosphorylation
Gene Expression
Proteins
Hunger
Biosynthetic Pathways
Epinephrine
Norepinephrine

Keywords

  • Adrenal medulla
  • Aging
  • Catecholamines
  • Dopamine β-hydroxylase
  • Phenylethanolamine n-methyltransferase
  • Protein kinases
  • Tyrosine hydroxylase

ASJC Scopus subject areas

  • Medicine(all)

Cite this

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title = "Effects of age on the glucoregulatory response following acute glucoprivation induced by 2-deoxyglucose (2DG) in the Adrenal medulla of Sprague Dawley rats",
abstract = "OBJECTIVES: Impairment in glucose homeostasis is one of the factors that may alter the feeding drive, hunger and satiety signals, which essential to maintain a sufficient level of energy for daily activities especially among the elderly. Adrenal medulla is one of the important organs that involves in glucose homeostasis through secretion of catecholamines. The catecholamines biosynthesis pathway utilizes various enzymes and protein kinases. The aims of this study are to investigate the effects of age on the biosynthetic pathway of catecholamines in adrenal medulla by determining the level of blood glucose and blood catecholamines, the gene and protein expression of biosynthetic catecholamine enzymes (TH, DBH and PNMT) as well as protein kinase substrates that involved in the phosphorylation of TH in 2DG-induced rats. METHODS: Adrenal medulla from male Sprague Dawley rats at the age of 3-months (n=12) and 24-months (n=12) were further divided into two groups: 1) treatment group with 2DG to create glucoprivation condition and 2) the vehicle group which received normal saline as control. RESULTS: The results showed that the level of glucose, adrenaline and noradrenaline were increased in response to acute glucoprivation conditions in both young and old rats. No age-related differences were found in the basal gene expression of the enzymes that involved in the catecholamines biosynthesis pathway. Interestingly the expressions of TH and DBH protein as well as the level of TH phosphorylation at Ser40, PKA, PKC and ERK1/2 substrates were higher in basal condition of the aged rats. However, contradicted findings were obtained in glucoprivic condition, which the protein expressions of DBH, pERKl/2 and substrates for pPKC were increased in young rats. Only substrate for pCDK was highly expressed in the old rats in the glucoprivic condition, while pPKC and pERKl/2 were decreased significantly. The results demonstrate that adrenal medulla of young and old rats are responsive to glucose deficit and capable to restore the blood glucose level by increasing the levels of blood catecholamines.",
keywords = "Adrenal medulla, Aging, Catecholamines, Dopamine β-hydroxylase, Phenylethanolamine n-methyltransferase, Protein kinases, Tyrosine hydroxylase",
author = "Muda, {Nor Azura} and Hajira Ramlan and {Ahmad Damanhuri}, {Mohd Hanafi}",
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T1 - Effects of age on the glucoregulatory response following acute glucoprivation induced by 2-deoxyglucose (2DG) in the Adrenal medulla of Sprague Dawley rats

AU - Muda, Nor Azura

AU - Ramlan, Hajira

AU - Ahmad Damanhuri, Mohd Hanafi

PY - 2017/1/1

Y1 - 2017/1/1

N2 - OBJECTIVES: Impairment in glucose homeostasis is one of the factors that may alter the feeding drive, hunger and satiety signals, which essential to maintain a sufficient level of energy for daily activities especially among the elderly. Adrenal medulla is one of the important organs that involves in glucose homeostasis through secretion of catecholamines. The catecholamines biosynthesis pathway utilizes various enzymes and protein kinases. The aims of this study are to investigate the effects of age on the biosynthetic pathway of catecholamines in adrenal medulla by determining the level of blood glucose and blood catecholamines, the gene and protein expression of biosynthetic catecholamine enzymes (TH, DBH and PNMT) as well as protein kinase substrates that involved in the phosphorylation of TH in 2DG-induced rats. METHODS: Adrenal medulla from male Sprague Dawley rats at the age of 3-months (n=12) and 24-months (n=12) were further divided into two groups: 1) treatment group with 2DG to create glucoprivation condition and 2) the vehicle group which received normal saline as control. RESULTS: The results showed that the level of glucose, adrenaline and noradrenaline were increased in response to acute glucoprivation conditions in both young and old rats. No age-related differences were found in the basal gene expression of the enzymes that involved in the catecholamines biosynthesis pathway. Interestingly the expressions of TH and DBH protein as well as the level of TH phosphorylation at Ser40, PKA, PKC and ERK1/2 substrates were higher in basal condition of the aged rats. However, contradicted findings were obtained in glucoprivic condition, which the protein expressions of DBH, pERKl/2 and substrates for pPKC were increased in young rats. Only substrate for pCDK was highly expressed in the old rats in the glucoprivic condition, while pPKC and pERKl/2 were decreased significantly. The results demonstrate that adrenal medulla of young and old rats are responsive to glucose deficit and capable to restore the blood glucose level by increasing the levels of blood catecholamines.

AB - OBJECTIVES: Impairment in glucose homeostasis is one of the factors that may alter the feeding drive, hunger and satiety signals, which essential to maintain a sufficient level of energy for daily activities especially among the elderly. Adrenal medulla is one of the important organs that involves in glucose homeostasis through secretion of catecholamines. The catecholamines biosynthesis pathway utilizes various enzymes and protein kinases. The aims of this study are to investigate the effects of age on the biosynthetic pathway of catecholamines in adrenal medulla by determining the level of blood glucose and blood catecholamines, the gene and protein expression of biosynthetic catecholamine enzymes (TH, DBH and PNMT) as well as protein kinase substrates that involved in the phosphorylation of TH in 2DG-induced rats. METHODS: Adrenal medulla from male Sprague Dawley rats at the age of 3-months (n=12) and 24-months (n=12) were further divided into two groups: 1) treatment group with 2DG to create glucoprivation condition and 2) the vehicle group which received normal saline as control. RESULTS: The results showed that the level of glucose, adrenaline and noradrenaline were increased in response to acute glucoprivation conditions in both young and old rats. No age-related differences were found in the basal gene expression of the enzymes that involved in the catecholamines biosynthesis pathway. Interestingly the expressions of TH and DBH protein as well as the level of TH phosphorylation at Ser40, PKA, PKC and ERK1/2 substrates were higher in basal condition of the aged rats. However, contradicted findings were obtained in glucoprivic condition, which the protein expressions of DBH, pERKl/2 and substrates for pPKC were increased in young rats. Only substrate for pCDK was highly expressed in the old rats in the glucoprivic condition, while pPKC and pERKl/2 were decreased significantly. The results demonstrate that adrenal medulla of young and old rats are responsive to glucose deficit and capable to restore the blood glucose level by increasing the levels of blood catecholamines.

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KW - Tyrosine hydroxylase

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