THE INTERRELATIONSHIP BETWEEN POLYAMINES AND THE L-ARGININE NITRIC-OXIDE PATHWAY IN THE HUMAN PLACENTA

Nitric oxide (NO) and polyamines are both products of L-arginine metab olism In placental villous tissue NO and polyamines have been shown to be synthesized although the physiological significance is not known. We have measured polyamine (putrescine, spermidine and spermine) conce ntrations and nitric oxide synthase activities (NOS) in first trimeste r and term placentae from normal and abnormal pregnancies, but no diff erence was observed in polyamine concentrations between normal term an d placentae from growth-retarded and pre-eclamptic pregnancies. Signif icantly higher levels of polyamines were found in first trimester when compared to normal term placentae and there was a significant correla tion between NOS activity and the cellular polyamine levels. Cultures of a trophoblast cell line, BeWo, have been used to study the interact ion of added polyamines on NOS activity. Although there was a general tendency for all the polyamines to inhibit NOS activity only putrescin e was able to significantly inhibit NO production by these cells. It i s thought that the L-arginine-NO-polyamine pathway may have a physiolo gical role during pregnancy. (C) 1995 Academic Press, Inc.