NORMALIZATION OF TYROSINE-HYDROXYLASE ACTIVITY IN-VIVO IN THE STRIATUM OF TRANSGENIC MICE CARRYING HUMAN TYROSINE-HYDROXYLASE GENE - A MICRODIALYSIS STUDY

Using a microdialysis method, we observed a similar steady-state L-3,4 -dihydroxyphenylalanine accumulation in the striatum of transgenic mic e carrying the human tyrosine hydroxylase (TH) gene after NSD-1015 per fusion (10(-4) M) as compared to nontransgenic mice. Basal extracellul ar levels of 3,4-dihydroxyphenylacetic acid before the perfusion of NS D-1015 were also comparable in both transgenic and non-transgenic stri ata. The results suggest that the in vivo activity of TH in the striat um of transgenic mice was retained to the normal level by some regulat ory mechanism(s) in spite of the increased expression of the enzyme pr otein.