Incorporation of intracisternally administered L-[methyl-3H]methionine and S-adenosyl-L-[methyl-3H]-methionine into rat brain phospholipids.
The incorporation of intracisternally injected L-[methyl-3H]methionine [( 3H]Met) or S-adenosyl-L-[methyl-3H]methionine (Ado[3H]Met) into rat brain AdoMet and phospholipid pools was examined. When [3H]Met was administered, both AdoMet and phospholipid pools were labeled. However, exogenously injected Ado[3H]Met did not serve as a substrate for phospholipid-N-methyltransferases. It was concluded that only Ado[3H]Met formed in situ was utilized to methylate phospholipids and that this process was initiated on the cytoplasmic side of the membrane. The apparent biological half-life in brainstem of phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine formed from [3H]Met was 1.4 and 1.7 days, respectively. The half-life of phosphatidylcholine could not be determined due to interference from peripheral sources.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D006207:Half-Life; D007276:Injections, Intraventricular; D008297:Male; D008715:Methionine / Q000008:administration & dosage / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000008:administration & dosage / Q000378:metabolism*; D013997:Time Factors
D010743:Phospholipids; D012436:S-Adenosylmethionine; D008715:Methionine