Biology Department, Hillsdale College, Hillsdale, MI 49242-1205, USA.
Comp Biochem Physiol C Toxicol Pharmacol. 2009 Jul;150(1):107-12. doi: 10.1016/j.cbpc.2009.03.005. Epub 2009 Apr 1.
The effects of exogenous ethanol and/or folic acid on endogenous homocysteine (HoCys) and SAM (S-adenosylmethionine)/SAH (S-adenosylhomocysteine) levels in chick brains were studied at 11 days of development. Embryonic EtOH (3.0 mmol/kg egg) exposure caused a 1.6-fold increase in brain HoCys levels and a 9-fold decrease in brain SAM/SAH levels as compared to controls (p<or=0.05). Brain HoCys and SAM/SAH levels returned to control values when injected with a mixture of EtOH and folic acid (3.0 mmol EtOH/kg egg and 34 mumol folic acid/kg egg). The effects of exogenous EtOH on the remethylation pathway, as measured by 10-formyltetrahydrofolate dehydrogenase (10-FTHF DH) activities, and the transsulfuration pathway, as measured by taurine levels, were studied at 18 days of development. A single dosage of EtOH (3.0 mmol/kg egg; E(0)) and two daily dosages of EtOH (E(0-1)) failed to influence brain and hepatic 10-FTHF DH activities when compared to controls. However, three daily dosages of EtOH (E(0-2)) caused approximately a two-fold increase in brain 10-FTHF DH activities and a three-fold increase in hepatic 10-FTHF DH activities as compared to controls (p<or=0.05). Three daily EtOH dosages (E(0-2)) caused reduced taurine levels in both brain and hepatic tissues (p<or=0.05). Meanwhile, a single EtOH dosage (E(0)), two daily EtOH dosages (E(0-1)), and three daily EtOH dosages (E(0-2)), caused reduced hepatic taurine levels as compared to controls (p<or=0.05).
在鸡胚发育 11 天时，研究了外源性乙醇和/或叶酸对鸡脑中内源性同型半胱氨酸（HoCys）和 SAM（S-腺苷甲硫氨酸）/SAH（S-腺苷同型半胱氨酸）水平的影响。与对照组相比，胚胎乙醇（3.0mmol/kg 卵）暴露导致脑 HoCys 水平增加 1.6 倍，脑 SAM/SAH 水平降低 9 倍（p<0.05）。当注射乙醇和叶酸混合物（3.0mmol/kg 卵乙醇和 34μmol/kg 卵叶酸）时，脑 HoCys 和 SAM/SAH 水平恢复到对照值。在发育 18 天时，研究了外源性乙醇对 remethylation 途径（通过 10-甲酰四氢叶酸脱氢酶（10-FTHF DH）活性测量）和转硫途径（通过牛磺酸水平测量）的影响。单次剂量的乙醇（3.0mmol/kg 卵；E(0)) 和两次每日剂量的乙醇（E(0-1)) 与对照组相比，并未影响脑和肝 10-FTHF DH 活性。然而，三次每日剂量的乙醇（E(0-2)) 导致脑 10-FTHF DH 活性增加约两倍，肝 10-FTHF DH 活性增加三倍，与对照组相比（p<0.05）。三次每日乙醇剂量（E(0-2)) 导致脑和肝组织中的牛磺酸水平降低（p<0.05）。同时，单次乙醇剂量（E(0))、两次每日乙醇剂量（E(0-1)) 和三次每日乙醇剂量（E(0-2)) 导致肝组织中的牛磺酸水平降低，与对照组相比（p<0.05）。
