THE COMPARATIVE DISTRIBUTION OF C14-LABELED 2-DIMETHYLAMINOETHANOL AND CHOLINE IN THE MOUSE

¹ Departments of Pharmacology and Biochemistry, Division of Basic Health Sciences, Emory University, Atlanta, Georgia

The time course distribution of radioactivity from dimethylaminoethanol-1,2 C¹⁴, cholinemethyl -C¹⁴ and choline-1,2 C¹⁴ in the acidsoluble, lipid, and protein fractions of mouse brain and liver was determined following the intraperitoneal injection of from 0.1 to 150 mg/kg of the labeled compounds. Incorporated radioactivity into choline and choline derivatives of the acid-soluble and lipid extracts was determined by carrier technique. Incorporation of radioactivity into protein methionine was also followed. Dimethylaminoethanol was incorporated and retained by the brain to a greater extent than choline, although choline was a more effective immediate precursor of acidsoluble and lipid choline. Label from choline appeared in the respiratory carbon dioxide and was excreted in the urine at a higher rate than the label from dimethylaminoethanol. The relative efficacy of dimethylaminoethanol and choline as precursors of brain acid-soluble and lipid choline and the implication of the results obtained to the pharmacological properties of dimethylaminoethanol was discussed.