Reduced de novo synthesis of 5-methyltetrahydrofolate and reduced taurine levels in ethanol-treated chick brains.
In previous studies, exogenous ethanol (3 mmol EtOH/kg egg) caused a 1.6-fold increase in chick brain homocysteine (HoCys) levels at 11 days of development and the mixture of 3 mmol EtOH/kg egg and 34 micromol folic acid/kg egg attenuated EtOH-induced increases in chick brain HoCys levels. Because HoCys is converted to methionine utilizing the methyl donor, 5-methyltetrahydrofolate (5-methyl THF), we studied whether exogenous ethanol (3 mmol EtOH/kg egg) or the mixture of 3 mmol EtOH/kg egg and 34 micromol 5-methyl THF/kg egg inhibited chick brain 10-formyltetrahydrofolate dehydrogenase (10-FTHF DH; EC 1.5.1.6) activities and brain N5, N10-methylenetetrahydrofolate reductase (MTHFR; EC 1.5.1.20) activities at 11 days of development. Three daily dosages of 3 mmol EtOH/kg egg (E0-2) caused approximately a 7-fold reduction in brain 10-FTHF DH activities and approximately a 1.9-fold reduction in brain MTHFR activities as compared to controls at 11 days of development (p<or=0.05). Because HoCys is also removed by the transsulfuration pathway, which synthesizes taurine, we studied whether exogenous ethanol (3 mmol EtOH/kg egg) or the mixture of 3 mmol EtOH/kg egg and 34 micromol 5-methyl THF/kg egg influenced chick brain taurine levels. In EtOH-treated and EtOH and 5-methyl THF-treated embryos, brain taurine levels decreased by approximately 5.5-fold and 6.2-fold as compared to controls, respectively (p<or=0.05). Exogenous 5-methyl THF failed to attenuate EtOH-induced decreased brain taurine levels at 11 days of development.
Berlin
Kelsey N
KN
Hillsdale College, Biology Department, 278 N. West Street, Hillsdale, MI 49242-1205, USA.
Cameron
Lauren M
LM
Gatt
Meredith
M
Miller
Robert R
RR
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000196:embryology / Q000201:enzymology; D002642:Chick Embryo; D002645:Chickens / Q000378:metabolism*; D000431:Ethanol / Q000633:toxicity*; D006710:Homocysteine / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D013654:Taurine / Q000378:metabolism*; D013763:Tetrahydrofolates / Q000096:biosynthesis* / Q000494:pharmacology
D013763:Tetrahydrofolates; D006710:Homocysteine; D013654:Taurine; D000431:Ethanol; D010088:Oxidoreductases; C005984:5-methyltetrahydrofolate