title: Changes associated with early weaning in the activity of tyrosine hydroxylase in the caudate nucleus of the piglet.
abstract: 1. Early weaning in piglets is associated with changes in dopamine metabolism in the caudate nucleus. In particular, a decrease in the amount of the enzyme tyrosine hydroxylase was observed. 2. An analysis of the kinetic properties of tyrosine hydroxylase from the caudate nucleus of early-weaned piglets shows that there is a relative increase in the activity of the enzyme which may indicate a mechanism compensating for the decreased amount of enzyme. 3. The increase in activity is mediated through a decrease in the Km for tetrahydrobiopterin and is reversed, in vitro, when the tissue is homogenized at pH values greater than 8.0.
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001708:Biopterins / Q000031:analogs & derivatives / Q000378:metabolism; D002421:Caudate Nucleus / Q000201:enzymology*; D007700:Kinetics; D007980:Levodopa / Q000096:biosynthesis; D013552:Swine; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D014886:Weaning
chemical_list: D001708:Biopterins; D007980:Levodopa; D014446:Tyrosine 3-Monooxygenase; C003402:sapropterin