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A Study on the Placental Transport Mechanism of Vitamin K 2 (MK‐4)
Author(s) -
Iioka Hideaki,
Akada Shinobu,
Hisanaga Hiroyasu,
Shimamoto Takako,
Yamada Yoshihiko,
Moriyama Ikuko S.,
Ichijo Motohiko
Publication year - 1992
Publication title -
asia‐oceania journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 0389-2328
DOI - 10.1111/j.1447-0756.1992.tb00299.x
Subject(s) - placenta , vitamin , venous blood , vitamin d and neurology , fetus , medicine , chemistry , endocrinology , pregnancy , andrology , biology , genetics
The present study was primarily concerned with in vitro investigation of vitamin K 2 (MK‐4) transport using human placental villous tissues, with the objective of elucidating the placental transport mechanism of vitamin K 2 .1 When vitamin K 2 (MK‐4) was not administered to gravidae, the observed concentrations of vitamin K 2 were 0.32±0.07 ng/ml in the maternal venous blood, undetectable in umbilical venous blood, and 1.01 ±0.37 ng/g wet tissue in the placental villous tissue. 2 When vitamin K 2 was administered to gravidae, (20 mg/day X 7 days per os), the corresponding concentrations were 0.89±0.21 ng/ml in the maternal venous blood, 0.18±0.06 ng/ml in umbilical venous blood, and 5.38± 1.05 ng/g wet tissue in the placental villous tissue. 3 In vitro studies using placental villous tissue indicated that vitamin K 2 transport into villous tissue is not active, but suggested the existence of a highly vitamin K 2 specific transport system in the human placenta. On the other hand, the results of comparison studies of transport of vitamin K 2 and vitamin K 1 into villous tissue indicated that transport activity with respect to the former vitamin was higher. Moreover, comparison of vitamin K 2 transport into villous tissue at the end of the first trimester and at full term revealed that transport was somewhat higher during the final stage.In summary, the above results indicated that whereas transport of vitamin K 1 into the fetus is not especially pronounced, transport into the placental villous tissue is comparatively good.