title: The transport of thiamine, riboflavin and pyridoxal 5'-phosphate by human placenta.
abstract: In the present examination the concentrations of thiamine, riboflavin and pyridoxal 5'-phosphate in blood plasma of pregnant women and venous and arterial cord plasma were determined. In maternal plasma the concentration was 4.5 nmol/l (thiamine), 22.2 nmol/l (PLP), 8.7 nmol/l (free riboflavin) and 84.5 nmol/l (FAD + FMN). In venous cord plasma the concentration was 45.9 nmol/l (thiamine), 112.1 nmol/l (PLP), 40.6 nmol/l (free riboflavin) and 49.1 nmol/l (FAD + FMN). Therefore the gradients of concentration between maternal plasma and venous cord plasma were 1:10 for thiamine, 1:4.7 for free riboflavin and 1:5 for PLP. For the coenzyme forms of vitamin B2 the maternal circulation showed the higher concentration (1.7:1). Therefore an active transplacentar transport mechanism was assumed. The vitamin concentrations in cord arteria were significantly lower than that in cord vene, indicating a massive retention by the fetus.
authors.affiliation: Inst. f. Ernährungswissenschaft, Justus Liebig-Universität Giessen, FRG.
authors.forename: J
authors.initials: J
authors.lastname: Zempleni
authors.forename: G
authors.initials: G
authors.lastname: Link
authors.forename: W
authors.initials: W
authors.lastname: Kübler
mesh_terms: D000293:Adolescent; D000328:Adult; D001692:Biological Transport / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011732:Pyridoxal Phosphate / Q000378:metabolism*; D012256:Riboflavin / Q000378:metabolism*; D013831:Thiamine / Q000378:metabolism*
chemical_list: D011732:Pyridoxal Phosphate; D012256:Riboflavin; D013831:Thiamine