Enzyme Comparative Study of Spermatozoa and Seminal Plasma in Normal and Subfertile Man

Abstract

A semiquantitative colorimetric micromethod (APIZYM) was used to study the enzyme profiles of seminal plasma and of spermatozoa. Reactions with 65 different substrates are simultaneously tested in a single specimen. These substrates (principally naphtolic) allow the detection of hydrolytic enzymes (esterases, phosphatases, and peptidases) and of dehydrogenases potentially involved in sperm metabolism and in the process of fertilization. The usual sperm enzymes were regularly observed: C₃-C₄ esterases, amino acid arylamidases, acrosine, phosphatases, glutamyl transpeptidase, and various osidases. Among the dehydrogenases we observed a striking predominance of the enzymes of the hexose monophosphate shunt and of LDH. Seminal plasma has an enzyme pattern very similar to that of spermatozoa except for the absence of acrosine and of some dehydrogenases. This unexpected similarity is discussed. The gametes from subfertile donors do not at first sight differ in their enzyme pattern from those from fertile donors. Moreover, we found no marked differences between zymograms of seminal plasma from normal, subfertile, or even azoospermic patients. Deep freezing does not modify the hydrolytic enzymes of human sperm either quantitatively of qualitatively, but the dehydrogenases of the hexose monophosphate shunt are adversely affected (60% loss of activity for G 6 PDH, and 30% for 6 PGDH); LDH is not affected. The consequences on fertilizing capacity of frozen semen are discussed.