The placenta serves, in part, as a barrier to exclude noxious substances from the fetus. In humans, a single-layered syncytium of polarized trophoblast cells and the fetal capillary endothelium separate the maternal and fetal circulations. P-glycoprotein is present in the syncytiotrophoblast throughout gestation, consistent with a protective role that limits exposure of the fetus to hydrophobic and cationic xenobiotics. We have examined whether members of the multidrug resistance protein (MRP) family are expressed in term placenta. After screening a placenta cDNA library, partial clones of MRP1, MRP2, and MRP3 were identified. Immunofluorescence and immunoblotting studies demonstrated that MRP2 was localized to the apical syncytiotrophoblast membrane. MRP1 and MRP3 were predominantly expressed in blood vessel endothelia with some evidence for expression in the apical syncytiotrophoblast. ATP-dependent transport of the anionic substrates dinitrophenyl-glutathione and estradiol-17-beta-glucuronide was also demonstrated in apical syncytiotrophoblast membranes. Given the cellular distribution of these transporters, we hypothesize that MRP isoforms serve to protect fetal blood from entry of organic anions and to promote the excretion of glutathione/glucuronide metabolites in the maternal circulation.

Nitric oxide synthase (NOS) is responsible for the biological production of nitric oxide (NO) in several organs. NOS activity has also been localized in the reproductive tract, although direct evidence for its presence in the human or bovine oviduct is still lacking. In the present study, four different techniques were used to identify the presence of NOS activity in human (n = 11) and bovine (n = 9) oviduct: (

Background. Although methadone maintenance is the standard treatment of opiate addiction in pregnancy, opinion as to its utility is divided. The aim of this study was to analyze polydrug abuse, pregnancy outcome and fetomaternal complications among pregnant women in a major Swiss methadone maintenance program. Methods. Prospective data collection of all pregnant opiate addicts and their neonates from 1996 to 2001. Results. Maternal complications occurred in 73% and fetal complications in 34% of the pregnancies. The average methadone dose at delivery in the 89 pregnancies was 40.9 AE 32.7 (0-150) mg/day. Sixty-four percent of the women were co-users of cocaine and/or heroin. Birthweight was lower in polydrug abusers than in near-exclusive methadone users (p ¼ 0.001). Conclusion. The high rate of maternal complications demonstrates the need for further improvement in antenatal management of opiate addiction in pregnancy. Methadone maintenance is inefficient in preventing pregnancy exposure to additional illicit drug consumption. Additional illicit heroin and/or cocaine abuse does not seem to increase the incidence of fetomaternal complications during pregnancy, but reverses the positive impact of methadone on birthweight. Heroin-assisted treatment may be a more effective method of minimizing the use of street drugs.

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