Prolonged epididymal sperm storage in vespertilionid and rhinolophid bats, provides an interesting experimental model for the study of spermatozoa epididymal maturation. We examined the presence of the cytoplasmic droplet, and the sequential induction of capacitation and the acrosome reaction in spermatozoa obtained from different epididymal regions (caput, corpus, cauda) throughout the annual reproductive cycle of Corynorhinus mexicanus (C. mexicanus). This is a vespertilionid bat that stores spermatozoa in the epididymis for several months after testes regression. The number of sperm recovered from the different epididymal regions indicate that epididymal transit in C. mexicanus is rapid. The persistence of a high percentage of sperm cells with cytoplasmic droplet in cauda epididymis was observed in addition to a low index of capacitation and acrosome reaction in sperm cells obtained from the corpus epididymis. There was a significant increase in the percentage of capacitated and acrosome reacted spermatozoa during the storage of sperm cells in the cauda epididymis and the percentage of capacitated spermatozoa was consistently, and significantly, higher (p < 0.05) in cauda compared to the corpus epididymis at all studied dates. Tthe process of epididymal maturation in C. mexicanus is completed in the caudal region of this organ encompassing a significant period. Our results also indicate that in C. mexicanus, and in other vespertilionid and rhinolophid bats that show the same temporal asynchrony in the function of male reproductive organs, the final phases of epididymal maturation and storage are, apparently, independent of testicular function.

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Abstract:In Chihuahuan Desert arid zone, particularly the states of Zacatecas and San Luis Potosi, Mexico, have been distinguished by its large mining activity, however, many of these mines are disuse, becoming potential refuges for various species of cave bats. Monitoring the potential roosts by Corynorhinus townsendii was made within the system of mines in the vicinity of the Sierra La Mojonera Flora and Fauna Protection Area, at Mexico's Central Highlands in the states of Zacatecas and San Luis Potosi. Which consisted of visual inspection inside, and mist netting at the entrance of different mines during an annual cycle. The main reproductive roosts for C. townsendii were identified. Spermatogenesis takes place during MaySeptember; the mating period in November-December, whereas the sequence of gestation-lactation occurred since March to August of the next year. These data confirm that C. townsendii in the area of study follow a seasonally monoestrous reproductive pattern, characterized by an asynchrony between the ovarian and spermatogenic cycles.

GGT initiates the degradation of both oxidized and reduced glutathione at the cell surface by cleaving the unique gamma glutamyl bond. The successive hydrolysis of oxidized or reduced CysGly by aminopeptidase or dipeptidase releases Gly, and cysteine/cysteine is recovered for intracellular synthesis of glutathione. In addition, GGT plays a major physiological role in providing cysteine to cells for GSH synthesis and protein synthesis, thereby playing a major role in antioxidant defense and normal growth. GGT is present in the epididymis, principally in caput. The catalytic activity of GGT is highest in the proximal epididymal regions and decreases toward the distal regions; participating in the epididymal sperm maturation process.In most mammals, epididymal sperm maturation takes place in a period not exceeding ten days, ending in the distal part of the corpus of the epididymis, before reaching the caudal region, which is responsible only for sperm storage; however, in C. mexicanus the epididymal sperm maturation ends in caudal epididymal region.For this reason, the main goal of the present study was to determine the relationship between the GGT activity through the caput and caudal epididymal regions, throughout annual cycle of Corynorhinus mexicanus bat.We found that the GGT activity appears to be important for epididymal sperm maturation in C. mexicanus bat in cephalic region, and important for protection against ROS epididymal caudal region.