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Genetics and exercise: an introduction
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Claude Bouchard, Henning Wackerhage
Mature sperms and oocytes are haploid cells, carrying only 23 instead of the normal 2 × 23 chromosomes in somatic cells. So how do we get from a normal cell with 46 chromosomes to a gamete? The answer is that this occurs during meiosis, a process by which female and male haploid gametes are generated. Spermatogenesis occurs in the testes and produces sperm in abundance. A subpopulation of these cells, spermatocytes, undergoes two meiotic divisions to form four haploid sperm cells. The process of female gamete production in the ovaries is called oogenesis. It begins during foetal development when thousands of primary oocytes are formed through mitosis. Primary oocytes enter meiosis but their meiotic progression is arrested until puberty with the onset of the menstrual cycle.
Alterations in Leydig Cell Morphology
Published in Tom O. Abney, Brooks A. Keel, The Cryptorchid Testis, 2020
Momokazu Gotoh, Koji Miyake, Hideo Mitsuya
Leydig1 first described the interstitial cells in the testis, which have since been known as Leydig cells. Bouin and Ancel2 postulated that these cells were involved in the synthesis of androgenic steroid hormones. Since then, a body of evidence has accumulated, both cytological and biochemical, to confirm their views.3–8 It is now well established that testosterone is produced from pregnenolone by a series of reactions carried out by enzymes sequestered in the mitochondria and smooth endoplasmic reticulum of Leydig cells.8,9 It is likewise widely accepted that testosterone synthesized by Leydig cells is essential for maintaining and stimulating normal spermatogenesis.10
Heterologous Pairing and Fertility in Humans
Published in Christopher B. Gillies, Fertility and Chromosome Pairing: Recent Studies in Plants and Animals, 2020
From the above, several important features stand out. First, spermatogenesis is an ongoing process, with multiplication from basic stem cells, whereas the number of oocytes in the human ovary is fixed at birth. Second, meiosis in the male is completed in approximately 74 d,37 while in the human female it is spread over an exceedingly long period of time, varying from 10 to 40 years or more.36 Third, with reference to potential fertility resulting from male and female meiosis, the extrusion of two polar bodies in the female allows for the elimination of chromosomally abnormal complements since the polar bodies eventually degenerate. This is not possible in the male, where all four products of meiosis are initially viable sperm.
Atrazine neural and reproductive toxicity
Published in Toxin Reviews, 2022
Hamidreza Sadeghnia, Sara Shahba, Alireza Ebrahimzadeh-Bideskan, Shabnam Mohammadi, Amir Mohammad Malvandi, Abbas Mohammadipour
Sperm is produced from germinal cells through spermatogenesis. The primary cell involved in spermatogenesis is spermatogonia (Fani et al. 2018). Fani et al. (2018) showed that atrazine dysregulates the process of spermatogenesis (Fani et al. 2018). This study revealed that atrazine exposure resulted in increased apoptosis in spermatogonia and primary spermatocytes and reduced sperm quality in mice. Another study reported that atrazine administration (300 mg/kg) to rats decreases sperm motility and counts by 25.8% and 27.6%, respectively (Kale et al. 2018). An increase in apoptotic cells number may be due to oxidative stress induced by atrazine. According to Kale et al. (2018), atrazine-induced oxidative damage in testis is associated with cyclooxygenase-2 (COX-2), an enzyme involved in various pathological conditions, and able to induce oxidative stress (Chae et al. 2008, Kale et al. 2018). Kale et al. (2018) investigated the effect of COX-2 inhibitor against atrazine-induced toxicity and observed histopathological improvement of testis in treated rats, which indicates that COX-2 plays a crucial role in atrazine-induced damages.
Effects of quetiapine administration on sperm quality and testicular histology
Published in Drug and Chemical Toxicology, 2022
Busra Korkut Celikates, Volkan Kilic, Ozlem Atli-Eklioglu, Merve Baysal, Gozde Aydogan-Kılıc, Seyda Ucarcan, Sinem Ilgin
Sperm concentration, motility, and morphology are considered essential markers of sperm quality (Payan-Carreira et al. 2013, Kumar and Singh 2015). Reference values of sperm parameters, such as concentration, motility, and morphology specified in Guide of the World Health Organization, were obtained from studies performed on fertile populations. According to the guide, men with values below reference values can be considered infertile (Menkveld 2001). In our study, sperm concentration was decreased, and abnormal sperm morphology was increased with QET-administration, dose-dependently. It has been shown that in subjects with sperm counts >106/mg cauda and abnormal morphology rates > 16%, fertility is positively related to sperm count and morphology, respectively (Chapin 1997). In our study, QET-induced sperm concentration and morphology alterations above the thresholds mentioned previously. Therefore, it is possible to relate QET treatment with infertility. Sperm quality and reproductive hormone levels offer information about the testicular function (Uhler et al. 2003). As mentioned above, alterations in reproductive hormone levels may cause impairment of spermatogenesis. At this point, it can be emphasized that hormonal disturbances are considered one of the major causes of adverse reproductive effects.
Radio-Protective effect of aminocaproic acid in human spermatozoa
Published in International Journal of Radiation Biology, 2022
Timur Saliev, Ildar Fakhradiyev, Shynar Tanabayeva, Yelena Assanova, Dinmukhamed Toishybek, Aigul Kazybayeva, Baimakhan Tanabayev, Marat Sikhymbaev, Aliya Alimbayeva, Yerzhan Toishibekov
It has been already demonstrated that ionizing radiation affects all stages of the spermatogenesis process (Wdowiak et al. 2019; David and Orwig 2020; Fuciarelli and Rollo 2021). Spermatogenesis is a complex physiological process of cell differentiation where diploid germ cell spermatogonia undergo proliferation and differentiation stages. Finally, it leads to the transformation of the spermatogonia into haploid spermatozoa. In the context of radio-sensitivity, the most vulnerable cell type is spermatogonia followed by spermatocytes and spermatids (young spermatozoa). Spermatozoa were used as a model for the presented study. Such a choice was dictated by the availability of sperm samples and the convenience of the laboratory experiments. However, future studies are needed to scrutinize the radio-protective effect of EACA on all phases of spermatogenesis.