BIOCHEMICAL MARKERS OF EARLY AND LATE SPERMATOGENESIS - RELATIONSHIP BETWEEN THE LACTATE DEHYDROGENASE-X AND CREATINE KINASE-M ISOFORM CONCENTRATIONS IN HUMAN SPERMATOZOA (VOL 43, PG 495, 1996)

As part of our research program on biochemical markers of sperm maturi ty, we have studied sperm creatine kinase (CK) and lactate dehydrogena se (LDH) concentrations and the isoform ratios of the CK-M [% CK-M/(CK -M + CK-B)] and LDH-X [% LDH-X/(LDH-X + LDH-a)] in 50 oligospermic and 95 normospermic men. Because the synthesis of LDH-X is initiated in e arly spermatogenesis, and that of CK-M commences in late spermiogenesi s simultaneously with cytoplasmic extrusion, we proposed two working h ypotheses: (1) LDH and CK concentrations reflect the retained cytoplas m in sperm, thus the activities of both enzymes will be related and wi ll be higher in oligospermic specimens, which have a higher incidence of immature spermatozoa; and (2) because in normally developed sperm b oth LDH-X and CK-M are present, there will be a correlation between LD H-X and CK-M ratios in the mature sperm populations. However, among me n with immature sperm samples with late spermiogenetic defect and dimi nished CK-M ratios, there will be two groups: one which completed sper matogenesis prior to spermiogenetic failure (normal LDH-X and diminish ed CK-M ratios), and another group with defects in both spermatogenesi s and spermiogenesis (low LDH-X and diminished CK-M ratios). Because o f this heterogeneity, LDH-X ratios will be a poor predictor of sperm m aturity. The data support the hypotheses: (1) LDH and CK concentration s were higher in oligospermic vs. normospermic men (P < 0.001). (2) Th e LDH and CK concentrations were related (r = 0.65, P < 0.001, N = 145 ), and there were inverse correlations between CK, LDH, LDH-X, or CK-M ratios vs. sperm concentrations (P < 0.001 in all four). (3) The CK-M and LDH-X ratios were different between the oligospermic and normospe rmic groups (P < 0.001), although the means of the LDH-X ratios were n arrower (LDH-X:1:1.3; CK-M:1:1.9). (4) Dividing the 145 samples by the cut-off value of mean minus 1 SD of the CK-M and LDH-X ratios (11% an d 32%, respectively) demonstrated that the CK-M ratios discriminated b etter than LDH-X ratios between the samples with mature and immature s perm. These data on the biochemical markers of early and late spermato genesis support the studies in which CK better reflected sperm quality than LDH or LDH-X (Orlando et al., 1994: Int J Androl 17:13-18) and t he >10% sperm CK-M ratio predicted with a rate of 30.4% per cycle the occurrence of pregnancies in a blinded study of 84 IVF couples (Huszar et al., 1992: Fertil Steril 57:882-888). (C) 1996 Wiley-Liss, Inc.