RESUMEN
Human placenta is an active metabolic organ. It defines a final set of quantitative and qualitative substances, transferred to the fetus. In view of high level of obstetric complications in Ukraine, in particular, preeclampsia, anemia, etc., we have undertaken a study of folate-dependent metabolism in human placenta. Disturbances of folate-dependent metabolism are considered as causes of pregnancy complications. Investigations carried out on 38 samples of term placenta, obtained after physiological pregnancy, and 58 samples obtained after pregnancy with wide-spread complications typical of Ukraine. We have estimated the level of folate, components of methionine cycle--methionine and homocysteine, and related with methionine cycle cysteine and glutathione and polymorphism of methylentetrahydrofolate reductase (MTHFR) catalyzes the irreversible conversion of 5,10-methyl-enetetrahydrofolate to 5-methyltetrahydrofolate, which serves as supplier of methyl group for methionine cycle. We have revealed, that C677T and T677T genotypes of MTHFR are represented more frequently in the samples from complicated pregnancies. In the samples-carriers of C/T genotype of MTHFR and in the group with complicated pregnancies the content of aminothiols and folates correlate in different directions with homocysteine level which serves as a marker of folate-dependent methionine cycle and related processes. On the basis of possitive correlation between homocysteine and cysteine in all investigated groups with different genotypes and the presence/absence of obstetrical complication we suggest the existence of transsulfuration pathway of homocysteine in the human placenta.