Firm conclusions about pathophysiologic mechanisms cannot be drawn from epidemiological studies alone; however, the current findings may reflect impaired renal tubular uptake, alterations in BHMT
flux, and activation of key elements in energy and insulin homeostasis, with potential ramifications also to mitochondrial function and methyl group metabolism.
Resultados: El analisis revelo 10 moleculas sobreexpresadas (Mupl, LRP1, P14KA, ALYREF y BHMT
) y 5 subexpresadas (PSME4, KEAP1, ELK3, FAM186B y PRELID 1) en un punto de corte de 1.5-fold-change.
To compensate for this decrease in MTR activity, the activity of BHMT
is induced after alcohol ingestion.
was decreased by arsenic deprivation in rats fed dietary choline.
Abbreviations: Ado, adenosine; BHMT
, betaine-homocysteine S-methyltransferase; CBS, cystathionine [beta]-synthase; DHF, dihydrofolate; DMG, dimethylglycine; Glu, glutamate; Gly, glycine; GSH, glutathione; MS, methionine synthase; MT, methyltransferase; MTHFR, methylenetetrahydrofolate reductase; SAH, S-adenosylhomocysteine; SAM, S-adenosylmethionine; THF, tetrahydrofolate; Zn, zinc.
For remethylation of homocysteine, a methyl group can be transferred either from N5-methyl tetrahydrofolate (THF) by methionine synthase, or from betaine by betaine homocysteine methyl transferase (BHMT
was significantly upregulated in the 20:5n-3, 18:3n-3, and 18:2n-6 groups.
The transsulfurating enzyme, cystathionine [beta]-synthase (CBS) is activated  and the remethylating enzyme, betane:homocysteine methyltransferase (BHMT
) is inhibited by Adomet and AdoHcy (Fi.1) .
Secondly, homocysteine can be re-methylated to form methionine, either via the betaine pathway through betaine-homocysteinemethyltransferase (BHMT
; EC 126.96.36.199) or by means of the tetrahydrofolate pathway (involving folates and vitamin B12) through methyltetrahydrofolate-homocysteine-methyltransferase (THFMT; EC 188.8.131.52), (Finkelstein and Martin, 1984; Xue and Snoswell, 1985; Snoswell and Xue, 1987; Kidd et al., 1997; Lewis, 2003).
Several other polymorphisms, including CBS 1080C>T and 699C>T (22, 23), transcobalamin-II (TCII) 776C>G (24-28) and 67A>G (29), reduced folate carrier-1 (RFC1) 80G>A (30-33), betaine homocysteine methyltransferase (BHMT
) 742G>A (34, 35), and paraoxonase-1 (PON1) 575A>G and 163T>A (36, 37), have been related to folate or Hcy status, and their possible associations with risk of cardiovascular disease and other diseases are under investigation.
For example, SNPs which code for methylation, such as MTHFR, MTRR, COMT, BHMT
Abbreviations: B12, vitamin [B.sub.12]; BHMT
, betaine homocysteine methyltransferase; DMA, dimethylarsinic acid; InAs, inorganic As; MMA, monomethylarsonic acid.