OBJECTIVE

To study the exchange of nucleotides and cellular gas-transmitters in the placenta and to find out their role in the genesis of preterm labor.

MATERIAL AND METHODS

Fifty-five patients were examined and made up two groups: the 1st (control) group included 27 clinically healthy women with uncomplicated pregnancy and labor at term (39—40 weeks). The 2nd (main) group included 28 pa-patients who developed spontaneous labor at 34—37 weeks’ gestation. Spectrophotometric, radioimmunological methods and immunoenzyme analysis were used to determine the content of acyclic and cyclic nucleotides and gas-transmitter exchange reactions in the placenta.

RESULTS

It was found that the development of preterm labor occurs against the background of a decrease in the content of acyclic nucleotides and nucleosides: adenosine triphosphoric acid, adenosine diphosphoric acid, adenosine, which is accompanied by increased energy deficiency, as well as increased activity of adenine deaminase, modification of adenosine deaminase activity — regulators of blood flow intensity and oxygen supply of the placenta. In addition, the level of cyclic nucleotides, the activity of their cyclase’s and protein kinases decreases. In preterm labor, a correlation was found in the placenta between the indicators of nucleotide metabolism and multifunctional gas transmitters: nitric oxide, carbon monoxide, hydrogen sulphide and the content of their enzymes — NO-synthase, histidine decarboxylase and cystathionine-synthase.

CONCLUSION

The imbalance of nucleotide metabolism against the background of impaired production of regulatory gas-transmitters may contribute to the premature development of labor activity. The revealed disorders expand our ideas about the molecular mechanisms of formation of this obstetric pathology and allow us to consider them as important components of the pathogenesis of preterm labor.