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  1. Muda NA, Ramlan H, Damanhuri HA
    Neuro Endocrinol. Lett., 2017 Jul;38(3):224-235.
    PMID: 28759191
    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, pERK1/2 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 pERK1/2 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.

    CONCLUSION: The present findings also suggest that, at least in rats, aging alters the protein expression of the biosynthetic catecholamine enzymes as well as protein kinase substrates that may attenuate the response to glucoprivation.

    Matched MeSH terms: Dopamine beta-Hydroxylase/genetics; Dopamine beta-Hydroxylase/metabolism
  2. Anderson TR, Slotkin TA
    Biochem Pharmacol, 1975 Aug 15;24(16):1469-74.
    PMID: 7
    Matched MeSH terms: Dopamine beta-Hydroxylase/metabolism
  3. Melati Khalid, Mohamad Aris Mohd Moklas
    MyJurnal
    Aromatic L-amino acid decarboxylase deficiency (AADC) is a rare autosomal recessive pediatric neurotransmitter disease. To date it remains poorly understood mainly due to an absence of a disease model. The dopaminergic neuroblastoma cell SH-SY5Y was chosen to develop our AADC deficiency model. These cells are not native dopamine synthesizers. Objective: To develop a dopamine-producing cellular model of AADC deficiency using SH-SY5Y neuroblastoma cells. Methods: Dopamine pathway proteins were identified with Western Blotting. Dopaminergic differentiation was attempted using all-trans retinoic acid (ATRA) with dopamine detection via HPLC-ECD post alumina extraction. Treatment with L-DOPA provided SH-SY5Y with excess precursor. RT-PCR was used to determine the expression of markers of mature neurons. Results: Western Blot screening identified AADC, dopamine β-hydroxylase and tyrosine hyrdoxylase proteins, indicative of a dopaminergic pathway. ATRA was unsuccessful in producing dopamine from the cells. L-DOPA treatment however, generated dopamine first visible as a HPLC-ECD peak 30 minutes post-incubation. Prior to this, SH-SY5Y dopamine synthesis from L-DOPA has never been documented. This de novo synthesis is then inhibited using benserazide to form our AADC deficiency cell model. RT-PCR showed that SH-SY5Y cells express markers of mature neurons in its ‘native’ state and is not affected by L-DOPA and benserazide treatment. This cell model will potentially benefit many areas of AADC deficiency research. Conclusion: SH-SY5Y cells produced HPLC-ECD measureable amounts of dopamine with the addition of L-DOPA. Our model of AADC deficiency is generated by quelling the dopamine production with Benserazide.
    Matched MeSH terms: Dopamine beta-Hydroxylase
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