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Published on: August 21, 2017
Alterations in Arginase-NO-synthase System of Spermatozoa in Human Subjects with Different Fertility Potential
Roman V Fafula1,2, Ulyana P Iefremova2, Olena K Onufrovych2
1Department of Biophysics, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine.
Background:
Infertility is an important worldwide problem which affects 10-15% of couples globally. Altered NO production has also been implicated in the pathogenesis of the male infertility. The present study was designed to evaluate the changes in the activity of NO-synthase (NOS) and arginase in spermatozoa of patients with infertility.
Methods:
The total NOS, Ca2+-dependent constitutive (cNOS) and Ca2+-independent inducible (iNOS) activity and arginase activity were assessed in sperm cells of patients with different forms of pathospermia.
Results:
We found a significant increase in iNOS activity, but significantly decreased cNOS and arginase activity in sperm cells of infertile men vs fertile, normozoospermic men (p<0.001). The arginase/NOS ratio significantly decreased compared to control group. The iNOS/cNOS ratio was drastically increased in patients with decreased fertility potential indicating predominance of iNOS. Men with leuko cytospermia were distinguished to have the most express iNOS activity.
Conclusions:
These observations provide evidence for a disturbed balance between the L-arginine metabolic pathways in sperm cells of infertile men. This imbalance includes the considerable activation of the inducible isoform of NO-synthase accompanied by significant inhibition of its constitutive isoform which indicates disturbances in NO production. In patients with decreased fertility potential the arginase/NOS was shifted towards predominance of iNOS-derived NO production.
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