ABSTRACT
The placental trophoblast is considered to act as a barrier between mother and fetus, mediating the exchange of various materials across the placenta. ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp) and multidrug-resistance protein (MRP) are expressed in the placenta and function as efflux transport systems for xenobiotics. In the present study, we aimed to determine the localization of MRP1 in the human placenta in comparison with that of P-gp. Western blotting analysis with human placental membrane vesicles indicated that P-gp and MRP1 are localized on the brush-border membranes and basal membranes, respectively. Immunohistochemical analysis with human normal full-term placenta showed that anti-P-gp monoclonal antibody F4 stained the brush-border side of the trophoblast cells, whereas anti-MRP1 monoclonal antibody MRPr1 stained the basal side. These results confirm that P-gp and MRP1 are located on the brush-border membranes and basal membranes, respectively, of human full-term placental trophoblast. MRP1 was also detected on the abluminal side of blood vessels in the villi. Accordingly, MRP1 may play a role distinct from that of P-gp, which is considered to restrict the influx of xenobiotics into the fetus.
Subject(s)
Multidrug Resistance-Associated Proteins/analysis , Trophoblasts/chemistry , ATP Binding Cassette Transporter, Subfamily B/analysis , ATP Binding Cassette Transporter, Subfamily B/metabolism , Basement Membrane/chemistry , Basement Membrane/cytology , Blotting, Western , Female , Humans , Immunohistochemistry , Multidrug Resistance-Associated Proteins/immunology , Placenta/cytology , Placenta/metabolism , Pregnancy , Transport Vesicles/chemistry , Trophoblasts/cytology , Trophoblasts/metabolismABSTRACT
We have investigated the correlation between the arterial blood ketone body ratio (AKBR) and beta-hydroxybutyric acid (HBAC) in the course of a 75 g glucose tolerance test. The correlation was revealed to be represented by an equation of Y = A + BX [X = log(HBAC), Y = log(AKBR)] with high significance. This expression existed in both normal individuals and patients with liver, biliary tract or pancreas disease. The postoperative course was unsatisfactory because of liver dysfunction in cases whose value B was more than -0.6 in bisegmentectomy and more than -0.45 in uni- or subsegmentectomy. The coefficient B in the equation was suggested to contribute to the evaluation of hepatic functional reserve.
