Freezing and storage effects on enzyme, electrolyte, and mineral compositions in canine prostatic fluid

BACKGROUND:There is a paucity of information about the storage stability of seminal plasma components in literature. OBJECTIVES:This study investigates the potential effects of storage at -18.0°C on the enzyme activities and concentrations of selected electrolytes and minerals in canine prostatic fluid. METHODS:Semen was obtained in fractions from ten male dogs, and the third ejaculate fraction was analyzed immediately after sampling and after storage at -18.0°C for 7 days. The following analytes were assessed: gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), sodium, potassium, total calcium, inorganic phosphate, magnesium, zinc, and copper. RESULTS:Whereas electrolyte and mineral concentrations were not affected by freezing and 7 days of storage, effects on the enzyme activities were variable. ALP, AST, and LDH activities were significantly decreased (P < .05) in the post-thaw samples compared with the freshly prepared samples. CONCLUSIONS:Because freezing and storage of seminal plasma at -18°C had an impact on the activity of some enzymes, analyses should be performed in fresh, not frozen samples.