Sara Allahkarami
Mojgan Atabakhsh
Mohammad Nabi Moradi
Hadi Ghasemi
Maryam Bahmanzadeh
Heidar Tayebinia

Background: Ammonia, urea, uric acid, and creatinine are the major non-protein nitrogenous compounds (NPNs). It is reported that the concentration of NPNs in the seminal plasma of normal and infertile individuals is different and sperm is affected by NPNs. Objectives: The aim of this study was to determine the quantities of ammonia, urea, uric acid, and creatinine in seminal plasma and the correlation of these compounds with the fertilization rate after an intracytoplasmic sperm injection (ICSI). Methods: The levels of ammonia, urea, uric acid, and creatinine were determined in seminal plasma collected from ۵۰ men. The ammonia and urea were determined by L-glutamate dehydrogenase and diacetyl monoxime method, respectively. Uric acid and creatinine were detected by enzymatic method and Jaffe reaction, respectively. The fertilization was evaluated around ۱۶–۱۸ hours post-ICSI on the appearance of ۲ pronuclei and ۲ polar bodies. The fertilization rate was calculated by the number of fertilized oocytes per the number of oocytes injected. Results: There was a significant negative correlation between seminal ammonia and sperm motility (P<۰.۰۵). Urea and creatinine had a negative correlation with respect to the sperm count (P<۰.۰۵). In addition, there was an inverse correlation between urea and uric acid of seminal plasma and sperm morphology (P<۰.۰۵). A significant negative correlation was found between seminal uric acid and urea with respect to the percentage of the fertilization rate (P<۰.۰۵). Conclusions: The findings of the present study showed that urea and uric acid in seminal plasma have a negative impact on the fertilization rate.