EVIDENCE THAT 5'-CYTIDINEDIPHOSPHOCHOLINE CAN AFFECT BRAIN PHOSPHOLIPID-COMPOSITION BY INCREASING CHOLINE AND CYTIDINE PLASMA-LEVELS

We examined the effects of orally administered 5'-cytidinediphosphocho line (CDP-choline) on arterial plasma choline and cytidine levels and on brain phospholipid composition in rats. Animals receiving a single oral dose of 100, 250, or 500 mg/kg showed peak plasma choline levels 6-8 h after drug administration (from 12 +/-1 to 17 +/- 2, 19 +/- 2, a nd 24 +/- 2 mu M, respectively), The area under the plasma choline cur ve at >14 mu M, i.e., at a concentration that induces a net influx of choline into the brain, was significantly correlated with CDP-choline dose, In rats receiving 500 mg/kg this area was 2.3 times that of anim als consuming 250 mg/kg, which in turn was 1.8 times that of rats rece iving 100 mg/kg. Plasma cytidine concentrations increased 5.4, 6.5, an d 15.1 times baseline levels, respectively, 8 h after each of the thre e doses. When the oral CDP-choline treatment was prolonged for 42 and 90 days, brain phosphatidylcholine concentrations increased significan tly (by 22-25%; p < 0.05) in rats consuming 500 mg/kg/day. Brain phosp hatidylethanolamine and phosphatidylserine concentrations also increas ed significantly under some experimental conditions; levels of other p hospholipids were unchanged.