Measurement of Alkaline Phosphatase in Canine Seminal Plasma – An Update

Abstract

In dogs, diagnosis of incomplete ejaculation and azoospermia can be made by measuring the activity of the enzyme alkaline phosphatase (AP) in seminal plasma. However, even though upper cut-off value of 5000 IU/l is given in the literature, results by different assays may vary considerably. Furthermore, no data exist concerning the stability of the enzyme during storage of frozen seminal plasma, and no recommendations for pre-analytic dilutions can be found. During the present study, we compared results from a conventional large scale wet chemistry analyzer to a widely used dry chemistry point of care system (POC) and established a best practice for pre-analytical dilutions. Furthermore, stability of enzyme activities in seminal plasma during storage at -18 °C for 24 h was evaluated. The average activity of AP in the 2nd fraction of normal ejaculates measured by Reflotron® was 107,328 IU/l. After 24 h of frozen storage, activities did not differ significantly (96,844 IU / l, p > 0.05). Fresh and frozen samples were analysed in parallel by the POC and conventional chemistry analyser, and the results compared that did not reveal a significant difference (p > 0.05). A dilution of seminal plasma with physiologic saline 1:100 prior to analysis was sufficient for the qualitative information whether AP activity is below or above 5000 IU/l. Present data show that AP measurement by a POC dry chemistry system is sufficiently accurate in diluted seminal plasma for the diagnosis of azoospermia and that seminal plasma can be stored frozen for 24h before analysis.

Biochemical components of seminal plasma and their correlation to the fresh seminal characteristics in Marwari stallions and Poitou jacks

“…[8]. In dogs, ALP activity is similarly found in the epididymides and in the semeniferous tubules [24,25] and can be used as a marker for ejaculation and tubular patency [25,26]. ALP activity has been found in seminal vesicle fluid in bulls and boars, and in prostatic secretions in many mammals [27].…”

Male infertility and copy number variants (CNVs) in the dog: a two-pronged approach using Computer Assisted Sperm Analysis (CASA) and Fluorescent In Situ Hybridization (FISH)

“…Seminal ALP is produced in the epididymis. In normal ejaculates, ALP concentrations are >5000 U/L; in cases of incomplete ejaculation, it is <5000 U/L and often <2000 U/L [23,24]. Oligo-azoospermic subjects showed ALP values higher than 5000 U/L.…”

Proteins of the canine seminal plasma

“…In fact, alkaline phosphatase, in alkaline pH, acts by catalyzing the hydrolysis of monophosphate esters such as fructose 1-phosphate, fructose 6-phosphate, and fructose 1,6-diphosphate (TESKE et al, 1986;KUTZLER, 2005). Measurement of the enzymatic activity of alkaline phosphatase in the canine SP has been used for the diagnosis of incomplete ejaculation or azoospermia in dogs (SCHAFER-SOMI et al, 2013), and a reduced concentration of alkaline phosphatase in the SP suggests bilateral obstruction of the vas deferens or epididymis (GOBELLO et al, 2002).…”

“…Studies have shown that different proteins could be used as biomarkers for the diagnosis of prostate pathologies such as benign prostatic hyperplasia (SAGOLS & NAVARO, 2013). In addition to prostate diseases, other reproductive -REVIEW -Ciência Rural, v.46, n.5, mai, 2016. disorders such as azoospermia (SCHAFER-SOMI et al, 2013) and obstruction of the vas deferens or epididymis (GOBELLO et al, 2002) could also be diagnosed using biomarkers.…”