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.

scholarly journals Testis stereology, seminiferous epithelium cycle length, and daily sperm production in the ocelot (Leopardus pardalis)

2010 ◽  
Vol 73 (2) ◽  
pp. 157-167 ◽  
Author(s):  
R.C. Silva ◽  
G.M.J. Costa ◽  
L.M. Andrade ◽  
L.R. França
Keyword(s):  
Cycle Length ◽  
Seminiferous Epithelium ◽  
Sperm Production ◽  
Leopardus Pardalis ◽  
Daily Sperm Production

scholarly journals Perturbation of spermatogenesis by androgen antagonists directly injected into seminiferous tubules of live mice

Reproduction ◽  
2007 ◽  
Vol 133 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Kaz Nagaosa ◽  
Atsushi Kishimoto ◽  
Ryoichi Kizu ◽  
Akihisa Nakagawa ◽  
Akiko Shiratsuchi ◽  
...  
Keyword(s):  
Seminiferous Epithelium ◽  
Assay System ◽  
Seminiferous Tubules ◽  
Permeability Barrier ◽  
Gonadal Function ◽  
Sperm Production ◽  
Physiological Conditions ◽  
Androgen Antagonists ◽  
Severe Impairment ◽  
Blood Testis Barrier

Natural and artificial substances present in the environment can affect our health. Testicular toxicants in particular are troublesome, because they disturb gonadal function of males. Translocation of substances into the seminiferous epithelium where sperm production proceeds is restricted due to the blood–testis barrier, but this permeability barrier temporarily disappears under physiological and sub-physiological conditions. This means that any substance could enter the seminiferous epithelium and disturb sperm production. To reduce the risk posed by such toxins, it is important to accurately determine which substances possess the toxicity. However, existing assay systems are not satisfactory in terms of both accuracy and sensitivity. Here, we report the establishment of such a system. We injected the androgen antagonists, flutamide and vinclozolin, directly into seminiferous tubules of live mice, which had been treated with busulfan for a temporal arrest of spermatogenesis, and the testes were histologically examined to see the effect of the injected materials on spermatogenesis that was in the process of recovery. The injection of either substance brought about a severe impairment of spermatogenesis at an amount over a million times smaller than that used in the previous assay systems where animals are administered with test substances outside of the testis. In contrast, these androgen antagonists at the same doses showed lesser effects when intratubularly or intraperitoneally administered into mice that had not been pretreated with busulfan. We propose that the method adopted in this study is a novel assay system to identify potential testicular toxicants.

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 Testis Morphometry, Seminiferous Epithelium Cycle Length, and Daily Sperm Production in Domestic Cats (Felis catus)

2003 ◽  
Vol 68 (5) ◽  
pp. 1554-1561 ◽  
Author(s):  
Luiz R. França ◽  
Christiane L. Godinho
Keyword(s):  
Cycle Length ◽  
Felis Catus ◽  
Seminiferous Epithelium ◽  
Domestic Cats ◽  
Sperm Production ◽  
Daily Sperm Production

scholarly journals Disruption of sexual function, FSH secretion, and spermiogenesis in rabbits following developmental exposure to vinclozolin, a fungicide

Reproduction ◽  
2006 ◽  
Vol 131 (4) ◽  
pp. 805-816 ◽  
Author(s):  
D N R Veeramachaneni ◽  
J S Palmer ◽  
R P Amann ◽  
C M Kane ◽  
T T Higuchi ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Low Dose ◽  
Seminiferous Tubules ◽  
Testicular Descent ◽  
High Dose ◽  
Sperm Production ◽  
Developmental Exposure ◽  
Serum Lh ◽  
Women And Children ◽  
Daily Sperm Production

We studied sequelae of prenatal plus infantile exposure of male rabbits to vinclozolin, because it is ingested by women and children. Female Dutch-Belted rabbits (7–10/group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide 0, 7.2, or 72 mg vinclozolin/kg dam’s body weight/day. Vinclozolin had no effect on maintenance of pregnancy, growth of pups, age at testicular descent or weight of organs. Concentrations of serum LH or testosterone at 6, 12, or 24 weeks of age were unaffected. However, FSH was lower (P< 0.05) in both vinclozolin groups at all three ages. Following injection of GnRH at 12 or 24 weeks, the increase in FSH was less (P< 0.05) in both vinclozolin groups, as was testosterone at 12 weeks of age. After full sexual maturity, 2 of 7 low dose rabbits were uninterested in female or male teasers and never achieved erection or ejaculation. Overall, rates of ejaculation failure were: control 0% (0/48), low dose 29% (12/42), and high dose 5% (3/60). Daily sperm production per gram of testis and total number of sperm per ejaculate in both vinclozolin groups were similar (P> 0.1) to controls. However, semen from vinclozolin rabbits contained over two times more (P< 0.05) morphologically abnormal spermatozoa, mostly nuclear and acrosomal defects, than semen from controls. Seminiferous tubules with degenerative changes were more frequent (P< 0.05) in vinclozolin rabbits than in controls. Lesions included syncytia of spherical spermatids and desquamation of germ cells. Hence, developmental exposure to vinclozolin caused presumably permanent changes in copulatory ability, secretion of FSH, and spermiogenesis.

The Relationship of Biopsy Evaluations and Testicular Measurements to Over-All Daily Sperm Production in Human Testes

1980 ◽  
Vol 34 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Larry Johnson ◽  
Charles S. Petty ◽  
William B. Neaves
Keyword(s):  
Sperm Production ◽  
Relationship Of ◽  
The Relationship ◽  
Daily Sperm Production

Reproductive effects of endosulfan on male offspring of rats exposed during pregnancy and lactation

1999 ◽  
Vol 18 (9) ◽  
pp. 583-589 ◽  
Author(s):  
P R Dalsenter ◽  
E Dallegrave ◽  
J Rb Mello ◽  
A Langeloh ◽  
R T Oliveira ◽  
...  
Keyword(s):  
Male Offspring ◽  
Male Rats ◽  
Male Rat ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Rat Offspring ◽  
Stage Of Development ◽  
Reproductive Effects ◽  
Pregnancy And Lactation ◽  
Daily Sperm Production

1 The reproductive effects of endosulfan on the male offspring of rats were examined. Dams were treated orally with 0, 1.5 or 3.0 mg endosulfan/kg from day 15 of pregnancy to postnatal day (PND) 21 of lactation. The male offspring rats were investigated at PND 65 or 140, corresponding to the pubertal and adulthood stage of development. 2 The dose of 3.0 mg endosulfan/kg induced a decrease in maternal body weight during pregnancy, but litter size and mean birth weight were not affected. Similarly, the age at testis descent and preputial separation was not affected on the male offspring. 3 The daily sperm production (6106) was permanently decreased in the highest dose group when investigated at puberty and at adulthood. At the lowest dose, however, the daily sperm production was significantly reduced only at puberty. 4 Histologically, the percentage of seminiferous tubules showing complete spermatogenesis was significantly decreased at puberty. This finding may explain the decrease in daily sperm production observed in the endosulfan-exposed male rats. 5 The results of this study show that low doses of endosulfan have no apparent effect on developmental landmarks or on the weight of reproductive and accessory sex organ. Daily sperm production was the most susceptible endpoint in the male offspring exposed to endosulfan during pregnancy and lactation. To further understand the reproductive effects of endosulfan on male rat offspring, additional reproductive and toxicokinetic studies should be carried out to determine the extent of endosulfan exposure in male rat offspring in utero and during lactation.

scholarly journals Chronic exposure of bisphenol S (BPS) affect hypothalamic-pituitary-testicular activities in adult male rats: possible in estrogenic mode of action

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Hizb Ullah ◽  
Faizan Ullah ◽  
Owais Rehman ◽  
Sarwat Jahan ◽  
Tayyaba Afsar ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Chronic Exposure ◽  
Structural Changes ◽  
Gonadosomatic Index ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Bisphenol S ◽  
Daily Sperm Production

Abstract Background The industrial revolution has resulted in increased synthesis and the introduction of a variety of compounds into the environment and their potentially hazardous effects have been observed in the biota. The present study was aimed to evaluate the potential endocrine-disrupting effects of chronic exposure to the low concentrations of bisphenol S (BPS) in male rats. Methods Weaning male Sprague-Dawley rats (22 days old) were either exposed to water containing 0.1% ethanol for control or different concentrations of BPS (0.5, 5, and 50 μg/L) in drinking water for 48 weeks in the chronic exposure study. After completion of the experimental period, animals were dissected and different parameters (hormone concentrations, histology of testis and epididymis, oxidative stress and level of antioxidant enzymes in the testis, daily sperm production (DSP), and sperm parameters) were determined. Results Results of the present study showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organ weights. Oxidative stress in the testis was significantly elevated while sperm motility, daily sperm production, and the number of sperm in epididymis were reduced. Plasma testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations were reduced and estradiol levels were high in the 50 μg/L-exposed group. Histological observations involved a significant reduction in the epithelial height of the testis along with disrupted spermatogenesis, an empty lumen of the seminiferous tubules, and the caput region of the epididymis. Conclusion These results suggest that exposure to 5 and 50 μg/L of BPS for the chronic duration started from an early age can induce structural changes in testicular tissue architecture and endocrine alterations in the male reproductive system which may lead to infertility in males.

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.

scholarly journals Testis structure, duration of spermatogenesis and daily sperm production in four wild cricetid rodent species (A. cursor, A. montensis, N. lasiurus, and O. nigripes)

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251256
Author(s):  
Dirceu A. Cordeiro ◽  
Guilherme M. J. Costa ◽  
Luiz R. França
Keyword(s):  
Environmental Changes ◽  
Gonadosomatic Index ◽  
Mammalian Species ◽  
Rodent Species ◽  
Seminiferous Tubules ◽  
Sperm Production ◽  
Wild Rodents ◽  
Rats And Mice ◽  
Very High ◽  
Daily Sperm Production

Although rodents represent approximately 40% of all living mammalian species, our knowledge regarding their reproductive biology is still scarce. Due to their high vulnerability to environmental changes, wild rodents have become beneficial models for ecological studies. Thus, we aimed to comparatively investigate key functional testis parameters in four sexually mature wild rodent species (A. cursor, A. montensis, N. lasiurus, and O. nigripes). These species belong to the Cricetidae family, which is the most diverse family of rodents in South America, with a total of ~120 species in Brazil. The results found for the gonadosomatic index and the sickled sperm head shape observed strongly suggest that the species here evaluated are promiscuous, prolific, and short-lived. The duration of spermatogenesis was relatively short and varied from ~35–40 days. Both the percentage of seminiferous tubules (ST) in the testis parenchyma (~95–97%) and the number of Sertoli cells (SC) (~48–70 million) per testis gram were very high, whereas a fairly good SC efficiency (~8–13 round spermatids per SC) was observed. In comparison to other mammalian species studied, particularly the rodents of the suborder Myomorpha (i.e. hamsters, rats and mice), the rodents herein investigated exhibited very high (~62–80 million) daily sperm production per testis gram. This impressive spermatogenic efficiency resulted mainly from the short duration of spermatogenesis and quite high values found for the ST percentage in the testis and the SC number per testis gram. We expect that the knowledge here obtained will help conservation programs and the proper management of wildlife.

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