Abstract
Liver is the most important site for choline metabolism and possesses all enzymes relating to three different metabolic pathways. In order to find the metabolic change of hepatic choline-flux concerning sex differences, senility and administration of hepatotoxine, two enzyme activities, one is choline dehydrogenase (EC 1.1.99.1), the initiating enzyme for oxidation pathway, and the other is choline kinase (EC 2.7.1.32) for Kennedy pathway, were measured with rat liver. A close correlation between choline dehydrogenase activity and body weight as well as liver weight was obtained on the normal feeding rats aging from 25 day-old to 12 month-old, totaling 132, independent of sex. Choline dehydrogenase activity of senile rat was significantly depressed. Upon ethionine feeding, choline dehydrogenase activity was considerably depressed. On the other hand, choline kinase activity was activated twice, presumably, for the metabolic compensation.
