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>>> Forrest's Mom <[log in to unmask]> 06/04/97 04:37am >>> >>>Nicotinic cholinergic regulation of tyrosine hydroxylase gene expression and catecholamine synthesis in isolated bovine adrenal chromaffin cells. Craviso, GL; Hemelt, VB and Waymire, JC J Neurochem. 59: 2285-96 (1992)<<< <<<Generation of Reactive Oxygen Species by Tyrosine Hydroxylase: A Possible Contribution to the Degeneration of Dopaminergic Neurons? Jan Haavik, Dept. of Biochemistry, Univ of Bergen, Norway 6/4/97 4:24 am>>> <<<Scientific American, June 97. Gene Therapy 6/4/97 12:59 am>>> Linda - Your three posts of 6/4/97 re: tyrosine suggest that adding the enzyme tyrosine hydroxylase (TH) to a patient's medication could create larger amounts of dopamine in the brain. TH is a catalyst which promotes a chemical change in the amino acid, Tyrosine [C9-H11-NO3]. Tyrosine is found in high protein foods such as fish, nuts and meat. Tyrosine helps the transformation to L-Dopa which changes into dopamine. However, whether this chemical reaction is taking place in the adrenal gland (leading to adrenaline) or in the brain where the reaction creates dopamine, the biosynthesis is rate-limited by the enzyme TH. Hence, the ingestion of large quantities of protein in a person's diet does not usually lead to the production of adrenaline. Since L-Dopa (an amino acid) is not rate-limited, the treatment of giving patients L-Dopa (levodopa) was devised as a way to increase the amount of dopamine formed in the brain. Stephan 52/6