Amino acid L-arginine belongs to essential amino acids, which is necessary for spermatogenesis, embrional and fetal development, growth and foetus development and also for the maintenance of the vascular tone and haemodynamics. It was noted, that NO-synthases and arginase activity in peripheral blood lymphocytes changes under the conditions of autoimmune diseases in humans, whereas L-arginine concentration in blood plasma significantly decreases in infection invasion and inflammation. It is assumed, that NO may participate in follicles maturation and ovulation and also in the regulation of the tone of ovarian and endometrium vessels.

The activity of NO-synthases and arginase in blood plasma and lymphocytes lysate in healthy women, pregnant women with physiologic course of pregnancy and in pregnant women with the risk of miscarriage was investigated. In Lviv Municipal Centre for Family Planning the following groups of women were examined due to ethical regulars: 20 relevantly gynaecologically and somatically healthy women (1st group); 22 relevantly healthy pregnant women with physiological course of gestational period (2nd group); 24 pregnant women with the risk of miscarriage (3rd group). The examined groups of women were homogenous due to age, gynaecologic, obstetric, infectologic and somatic anamnesis. In blood plasma and lymphocytes lysate NOsynthases and arginase activity, nitrite anion content (NO2-), L-arginine concentration in blood plasma were determined.

In healthy pregnant women eNOS activity in lymphocytes lysate was insignificantly higher, compared to indices in the group of non-pregnant healthy women, what is likely associated with the adaptive changes in lymphocytes under conditions of pregnancy development. At that, arginase activity and nitrite anion content in blood plasma significantly did not differ from the indices in non-pregnant women. L-arginine concentration in blood plasma insignificantly decreased, whereas its concentration in lymphocytes lysate coincided with the indices of the group of non-pregnant women. In general, significant changes in the system of NO-synthase/arginase in pregnant women in the first trimester were not revealed.

In women with the risk of miscarriage the significant rise of eNOS activity in lymphocytes lysate increased for 40% (p<0.05), compared to indices in pregnant women without risk of miscarriage. At that, arginase activity did not change and L-arginine concentration in blood plasma decreased for 21% (p<0.05) and in lymphocyts lysate it did not change. This shows that L-arginine concentration in the cytoplasm of lymphocytes remains stable and under conditions of increased eNOS activity L-arginine intake from blood plasma increases.

Obtained results, on one hand, indicate that in blood circulating lymphocytes in women with the risk of miscarriage the changes in L-arginine metabolism occur, the most sensitive are the changes of eNOS activity, simultaneously L-arginine concentration decreases in blood, on the other hand – the proinflammatory factors under conditions of the risk of miscarriage are not yet fully activated, whereas eNOS activity changes reflect the adoptive process. The conduction of appropriate therapy under these conditions may be beneficial for the preservation of pregrancy.

Keywords: NO-synthases and arginase activity, lymphocytes, blood, pregnant women with the risk of miscarriage

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