Epididymal maturation of spermatozoa and modulation of fertility in man (interference of the capacitation and maturation processes of spermatogenesis by blocking the SH groups)
Reyes, A.; Mercado, E.; Rosado, A.
Ginecologia y Obstetricia de Mexico 37(220): 53-67
1975
ISSN/ISBN: 0300-9041 PMID: 1123160 Document Number: 89895
The compound N-4-carboxy-3-hydroxy-phenyl maleimide (CPhM) that changes its fluorescent properties on binding to free -SH groups of proteins of intact and metabolically active human spermatozoa, was recently introduced into the field of fluorescent probes. The kinetics of the reaction of this compound showed that the concentration of -SH groups drastically decreases as the spermatozoal maturation proceeds in the epididymis, from 1.70 umoles/108 cells at the head of the epididymis (only 1 case) to 1.3 and .85 in the tail and ejaculation, respectively. Similar data were obtained when the epididymal maturation of rabbit spermatozoa was assessed by this method. The concentration of exposed -SH groups was found to be 1.5, .78, and .45 umoles/108 cells, respectively, in the same order as in the human case. When the exposed -SH groups of rabbit spermatozoa were blocked by the binding of CPhM, these cells are unable to be capacitated during 18 hours of incubation in the rabbit female genital tract. Similarly, the incubation of spermatozoids obtained from the tail of the epididymis with CPhM causes them to produce only 7% fertilization, instead of the normal rate of 80%. These findings confirm that it is possible to use compounds such as CPhM to inhibit the processes of maturation and capacitation of spermatozoa, thereby producing an effective method to control male fertility.