Duration of the cycle of the seminiferous epithelium and quantitative histology of the testis of the South American white-belly opossum (Didelphis albiventris), Marsupialia

1992 ◽  
Vol 4 (2) ◽  
pp. 213 ◽  
Author(s):  
GF Queiroz ◽  
JC Nogueira
Keyword(s):  
Leydig Cells ◽  
Tritiated Thymidine ◽  
Seminiferous Epithelium ◽  
South American ◽  
Sperm Production ◽  
Annual Reproductive Cycle ◽  
The South ◽  
Daily Sperm Production ◽  
Type A Spermatogonia ◽  
White Belly

The duration of the cycle of the seminiferous epithelium of the South American white-belly opossum, as obtained by autoradiography after intratesticular injection of tritiated thymidine, was estimated to be 17.3 +/- 0.1 days (mean +/- s.d.). Quantitative histological analysis was performed on testes from animals caught both in mating and non-mating periods of the annual reproductive cycle. Significant differences were found in the volumetric proportion of Leydig cells, but the spermatogenic yield remained constant throughout the year. The numerical ratio between type A spermatogonia and zygotene primary spermatocytes (1:12.0), as well as daily sperm production (4.8 x 10(6) sperm cells per g of testis parenchyma per day), were found to be lower than those reported in most eutherian mammals.

scholarly journals A comparative study of sperm production in two species of Australian arid zone rodents (Pseudomys australis, Notomys alexis) with marked differences in testis size

Reproduction ◽  
2001 ◽  
pp. 239-247 ◽  
Author(s):  
EJ Peirce ◽  
WG Breed
Keyword(s):  
Arid Zone ◽  
Seminiferous Epithelium ◽  
Testis Size ◽  
Sperm Production ◽  
Interspecific Differences ◽  
Long Duration ◽  
Sperm Counts ◽  
The Mean ◽  
Low Efficiency ◽  
Daily Sperm Production

The plains rat, Pseudomys australis, and the spinifex hopping mouse, Notomys alexis, show marked differences in the size of their testes and in the number of spermatozoa within the epididymides. In the present study, the dynamics of sperm production and the duration of sperm transit along the male excurrent ducts were compared between these two species. The durations of the cycle of the seminiferous epithelium, spermatogenesis and sperm transit were determined by tracking cells using autoradiography after [(3)H]thymidine incorporation. Daily sperm production was determined from counts of testicular spermatids after homogenization and further estimates of sperm transit were obtained by dividing sperm reserves within the various regions of the extratesticular ducts by the daily sperm production of the attached testis. In the plains rat, the mean duration of the cycle of the seminiferous epithelium was 11.2 days, the duration of spermatogenesis was 45 days, daily sperm production was 2.6 x 10(7) spermatozoa per gram of testis and epididymal transit of spermatozoa took approximately 9 days (caput 0.8 days; corpus 1.5 days; cauda 6.5 days). In contrast, in the hopping mouse, the mean duration of the cycle of the seminiferous epithelium was 14 days, the duration of spermatogenesis was 56 days and daily sperm production per gram of testis was < 1.0 x 10(7). Epididymal transit of spermatozoa was completed in about 4 days (caput + corpus < 1 day; cauda 3 days); however, spermatozoa may be stored for an additional 1.5-2.0 days in the vas deferens. These results indicate that, in addition to small testes, the hopping mouse shows a low efficiency of sperm production, a relatively long duration of spermatogenesis and rapid passage of spermatozoa through the epididymis, all of which contribute to low epididymal sperm counts. These data are considered in relation to interspecific differences in sperm competition.

scholarly journals Spermatogenesis: The Commitment to Meiosis

2016 ◽  
Vol 96 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Michael D. Griswold
Keyword(s):  
Reduction Division ◽  
Seminiferous Epithelium ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Morphological Transformation ◽  
Time Required ◽  
Relationship Of ◽  
Synthesis And Degradation ◽  
Daily Sperm Production ◽  
Stem Cell Pool

Mammalian spermatogenesis requires a stem cell pool, a period of amplification of cell numbers, the completion of reduction division to haploid cells (meiosis), and the morphological transformation of the haploid cells into spermatozoa (spermiogenesis). The net result of these processes is the production of massive numbers of spermatozoa over the reproductive lifetime of the animal. One study that utilized homogenization-resistant spermatids as the standard determined that human daily sperm production (dsp) was at 45 million per day per testis (60). For each human that means ∼1,000 sperm are produced per second. A key to this level of gamete production is the organization and architecture of the mammalian testes that results in continuous sperm production. The seemingly complex repetitious relationship of cells termed the “cycle of the seminiferous epithelium” is driven by the continuous commitment of undifferentiated spermatogonia to meiosis and the period of time required to form spermatozoa. This commitment termed the A to A1 transition requires the action of retinoic acid (RA) on the undifferentiated spermatogonia or prospermatogonia. In stages VII to IX of the cycle of the seminiferous epithelium, Sertoli cells and germ cells are influenced by pulses of RA. These pulses of RA move along the seminiferous tubules coincident with the spermatogenic wave, presumably undergoing constant synthesis and degradation. The RA pulse then serves as a trigger to commit undifferentiated progenitor cells to the rigidly timed pathway into meiosis and spermatid differentiation.

Sexual maturation of the Mongolian gerbil (Meriones unguiculatus): a histological, hormonal and spermatic evaluation

2016 ◽  
Vol 28 (6) ◽  
pp. 815 ◽  
Author(s):  
Maria Etelvina Pinto-Fochi ◽  
Ana Carolina Negrin ◽  
Wellerson Rodrigo Scarano ◽  
Sebastião Roberto Taboga ◽  
Rejane Maira Góes
Keyword(s):  
Mongolian Gerbil ◽  
Leydig Cells ◽  
Serum Testosterone ◽  
Meriones Unguiculatus ◽  
Sperm Production ◽  
Mature Adult ◽  
Drastic Increase ◽  
Testicular Morphology ◽  
Sexually Mature ◽  
Daily Sperm Production

This study determined the phases of sexual development of the male Mongolian gerbil (Meriones unguiculatus) based on an integrative analysis of testicular morphology, hormonal data and sperm parameters. Male gerbils were analysed at 1, 7, 14, 21, 28, 35, 42, 50, 60, 70, 90, 100 and 120 days of age. Body, testicular and epididymal weights increased up to Day 70, 60 and 90, respectively. The impuberal phase, characterised by the presence of gonocytes, extended until Day 14. The prepubertal period lasted until Day 42, when puberty was achieved and a drastic increase in serum testosterone levels, mature adult Leydig cells and elongated spermatids was observed. Gerbils at 60 days of age showed a remarkable number of spermatozoa in the testis, epididymidis caput/corpus and cauda, and at Day 70 the maximum daily sperm production was reached. However, the gerbil may be considered sexually mature only from Day 90 onward, when sperm reserves become stable. The total transit time of spermatozoa along the epididymis of sexually mature gerbils was 11 days, with 1 day in the caput/corpus and 10 days in the cauda. These data cover a lacuna regarding the reproductive parameters of this rodent and provide foundations for its use in testicular toxicology studies.

scholarly journals Neonatal hypothyroidism does not increase Sertoli cell proliferation in iNOS−/− mice

Reproduction ◽  
2017 ◽  
Vol 154 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Nathália L M Lara ◽  
Luiz R França
Keyword(s):  
Thyroid Hormones ◽  
Sertoli Cell ◽  
Leydig Cells ◽  
Testis Size ◽  
Additive Effects ◽  
Sperm Production ◽  
Wild Type ◽  
Neonatal Hypothyroidism ◽  
Laboratory Rodents ◽  
Daily Sperm Production

Sertoli cell (SC) proliferation in mice occurs until two weeks after birth and is mainly regulated by FSH and thyroid hormones. Previous studies have shown that transient neonatal hypothyroidism in laboratory rodents is able to extend SC mitotic activity, leading ultimately to higher testis size and daily sperm production (DSP) in adult animals. Moreover, we have shown that due to higher SC proliferation and lower germ cell apoptosis, iNOS deficiency in mice also results in higher testis size and DSP. Although the cell size was smaller, the Leydig cells (LCs) number per testis also significantly increased in iNOS−/−mice. Our aims in the present study were to investigate if the combination of neonatal hypothyroidism and iNOS deficiency promotes additive effects in SC number, testis size and DSP. Hypothyroidism was induced in wild-type (WT) and iNOS−/−mice using 6-propyl-2-thiouracil (PTU) through the mother’s drinking water from 0 to 20 days of age, and were sacrificed at adulthood. Our results showed that, in contrast to the WT mice in which testis size, DSP and SC numbers increased significantly by 20, 40 and 70% respectively, after PTU treatment, no additive effects were observed for these parameters in treated iNOS−/−mice, as well as for LC. No alterations were observed in spermatogenesis in any group evaluated. Although we still do not have an explanation for these intriguing findings, we are currently investigating whether thyroid hormones influence iNOS levels and/or counterbalance physiological effects of iNOS deficiency in testis function and spermatogenesis.

Duration of spermatogenesis and daily sperm production in the rodent Proechimys guyannensis

Zygote ◽  
2016 ◽  
Vol 24 (5) ◽  
pp. 783-793 ◽  
Author(s):  
Nathália L.M. Lara ◽  
Ivan C. Santos ◽  
Guilherme M.J. Costa ◽  
Dirceu A. Cordeiro-Junior ◽  
Antônio C. G. Almeida ◽  
...  
Keyword(s):  
Leydig Cells ◽  
Gonadosomatic Index ◽  
Cell Types ◽  
Seminiferous Tubules ◽  
Testis Weight ◽  
Sperm Production ◽  
The Mean ◽  
Neotropical Rodent ◽  
Very High ◽  
Daily Sperm Production

SummaryThe spiny rat (Proechimys guyannensis) is a neotropical rodent that is used in biomedical research, particularly research related to chronic resistance to epilepsy and infectious diseases. To our knowledge, there are few reports concerning the reproductive biology of this species. Therefore, besides providing basic biometric and morphometric data, in the present study we investigated testis function and spermatogenesis in adult spiny rats. The mean testis weight and gonadosomatic index obtained were 1.63 ± 0.2 g and 1.15 ± 0.1% respectively. Based on the development of the acrosomic system, 12 stages of the seminiferous epithelium cycle were characterized. Stages VI and VII presented the highest frequencies (~17–19%), whilst stages II to V showed the lowest frequencies (~2–4%). The most advanced germ cell types labelled at 1 h or 20 days after BrdU injections were respectively preleptotene/leptotene spermatocytes at stage VII and elongated spermatids at stage III. The mean duration of one cycle was 7.5 ± 0.01 days and the entire spermatogenic process lasted 33.7 ± 0.06 days (~4.5 cycles). The seminiferous tubules (ST) occupied ~96 ± 1% of the testis parenchyma, whereas Leydig cells comprised only 1.5 ± 0.4%. The number of Sertoli cells (SC) per testis gram and the SC efficiency (spermatids/SC) were respectively 78 × 106 ± 11 × 106 and 7.9 ± 1. The daily sperm production per testis gram (spermatogenic efficiency; daily sperm production (DSP)/g/testis) was 78 × 106 ± 8 × 106. To our knowledge, this spermatogenic efficiency is among the highest found for mammals investigated to date and is probably related to the very short duration of spermatogenesis and the very high ST percentage and SC number obtained for this species.

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