S-adenosylmethionine, S-adenosylhomocysteine and adenosine system. Age-dependent availability in rat brain.
The changes in activity of N-methyltransferase 1 and [3H]-S-adenosylhomocysteine binding were determined in cortical membranes preparations from newborn and 1-, 2- and 10-month-old rats. These parameters were significantly higher: +130 and 200%, respectively, in 1-day compared to 2-month-old rats (adult). With maturation, S-adenosylmethionine levels decreased (-24%) whereas adenosine levels increased gradually from 0.17 to 6.10 nmol/mg protein in forebrain or whole brain between 1-day and 10-month-old rats. The ontogenesis of adenosine receptors was studied. The A2 receptors were not detectable at 1 day. For A1 receptors, Kd and Bmax increased with age while for A2 receptors Kd and Bmax were similar between 9 days and 2 months of age.
Sarda
N
N
Department of Biological Chemistry, INSERM U205, Villeurbanne, France.
Reynaud
D
D
Gharib
A
A
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism*; D019830:Adenosine-5'-(N-ethylcarboxamide); D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D006710:Homocysteine / Q000031:analogs & derivatives*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008780:Methyltransferases / Q000378:metabolism; D050918:Phosphatidylethanolamine N-Methyltransferase; D051381:Rats; D011919:Rats, Inbred Strains; D012435:S-Adenosylhomocysteine / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000378:metabolism*
D006710:Homocysteine; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D012436:S-Adenosylmethionine; D012435:S-Adenosylhomocysteine; D008780:Methyltransferases; D050918:Phosphatidylethanolamine N-Methyltransferase; D000241:Adenosine