Enzymes of polyamine biodegradation pathway in amniotic fluid during the pregnancy compared with values of L/S ratio

Background: During the pregnancy the amount of polyamines spermine, spermidine and putrescine, rise rapidly in amniotic fluid. Polyamine oxidase (PAO) represents one of the key enzymes in catabolic pathway of polyamines. PAO catalyzes the oxidative deamination of spermine (Sp) or spermidine (Spd). The literature data documented that serum PAO activity increases in pregnancy. Diamine oxidase (DAO), histaminase, catalyses the oxidation of diamine putrescine or histamine. DAO is present in high concentrations in amniotic fluid. Amniotic fluid is the protective liquid for the baby in the mother’s uterus. The determination of the lecithin to sphyngomyelin (L/S) ratio is by far the most widely used and accepted method to assess the fetal lung immaturity. The idea of the present study was to elucidate the polyamine metabolism in amniotic fluid during the pregnancy, through investigation of polyamine oxidase (PAO) and diamine oxidase (DAO) activities, and to compare their activities with the values of lecithin/ sphingomielin ratio (L/S) ratio. Methods: The study included 170 pregnant women. The amniotic fluid samples were obtained using amniocentesis. The values of L/S ratio were estimated by a thin layer chromatography. PAO and DAO activities were measured by the spectrophotometric methods. Results: Our results confirmed that amniotic fluid possess PAO and DAO activity. The activities of both enzymes in amniotic fluid samples increase in parallel with the L/S ratio increase. Diamine oxidase activity was higher than polyamine oxidase activity. Conclusions: DAO and PAO activities may serve as markers of fetal lung maturity.