China 
Africa 
Explore chapters and articles related to this topic
Basic Chemical Hazards to Human Health and Safety — II
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
For males, the time required to restore the sperm count is a significant reproductive effect. Any toxic substance that interferes with the control mechanism for the male pituitary hormones, Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH), can lead to male infertility. LH and FSH are regulated by hypothalamic releasing factors, which are controlled by the pituitary and hypothalamus. LH stimulates Leydig cells, which synthesize steroid hormones, particularly testosterone, which controls the activity of accessory sex organs and the development of secondary sexual characteristics. FSH stimulates the Sertoli cells to initiate spermatogenesis and maintain optimal testicular function. Male germ cells are susceptible to toxic insult during the stages of spermatogenesis, in particular, by either being killed or undergoing heritable alterations or suffering non-heritable alterations that affect morphology, motility, and viability. Reduction of sperm count leads to male infertility, while mutated sperm may lead to adverse effects in a fertilized egg. Abnormal sperm raises the probability of spontaneous abortion, still birth, or any number of birth defects.
Azadirachta indica A. Juss)
Published in Yuli Rahmawati, Peter Charles Taylor, Empowering Science and Mathematics for Global Competitiveness, 2019
E. Lisanti, R.D. Wulandari, D. Sajuthi, M. Agil, R.I. Arifiantini, A. Winarto, Arwin
The decrease in testis weight that occurred in the treatment group was thought to be due to flavonoid content. Flavonoid compounds have androgenic properties that can inhibit Interstitial Cell Stimulating Hormone (ICSH) and so induce Sertoli cells to produce an Androgen Binding Protein (ABP) which functions to bind testosterone and induce spermatogenesis (Nandwa, 2014). High levels of testosterone in the blood that is not bound to ABP will cause negative feedback to the anterior pituitary, which stops the release of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH), causes reduced testosterone secretion by the Leydig cells in the testis. If the testosterone in the Leydig cells is reduced, it will result in an impaired meiotic division, so that the formation of spermatids and will also be disrupted. This will also cause a decrease in the number of sperm, and it will also affect the mass of the testis.
Reproduction
Published in Alan G. Heath, Water Pollution and Fish Physiology, 2018
In the males, the germ cells in the testes may be in synchronous or variable stages of development, depending on the species. These spermatogonia are surrounded by Sertoli and Leydig cells which provide support and regulation of spermatogenesis (Callard, 1991). The Leydig cells produce the androgens, primarily testosterone, ketotestosterone, and androstenodione. In male brook trout, testosterone and 11-ketostetosterone levels rise at spermiation and then fall rapidly thereafter (Sangalang and Freeman, 1974). “Female” sex steroids are also present in the males, as is testosterone in the female. Sperm production is a synchronous event in some teleosts whereas in others it is cyclic or continuous.
Lead acetate induces apoptosis in Leydig cells by activating PPARγ/caspase-3/PARP pathway
Published in International Journal of Environmental Health Research, 2021
Li Zhou, Susu Wang, Lina Cao, Xiangmei Ren, Yuanhong Li, Jihong Shao, Lichun Xu
Notably, Pb exposure is considered to induce apoptosis in a variety of tissues and cells by interfering with different pathways. Mitochondria play a central role in the regulation of apoptosis (Zhao and Zhang 2018). Chi et al. observed that Pb induced mitochondrial swelling and nuclear chromatin condensation, oxidative stress, energy metabolism disorder, thereby led to apoptosis in chicken livers (Chi et al. 2017). Pb decreased protein expression of B-cell lymphoma-2 (Bcl-2); increased expressions of tumor suppressor protein p53, Bcl-2 associated X protein (Bax), Cytochrome C (CytC) and caspase-3; and induced apoptosis in the chicken brain tissues and embryonic neurocytes (Flora et al. 2012). Wang et al. found that Pb had time-dependent manners on NO content, endoplasmic reticulum-related genes, Bcl-2, and caspase-3 expressions in chicken kidneys (Wang et al. 2018). Leydig cells secrete testosterone, which is essential in the maintenance of spermatogenesis and male fertility (Walker 2011) and may play a critical role in protecting the testis from damage caused by toxicants or stress (Gong et al. 2009). Thoreux-Manlay et al. (1995) put forth that Leydig cells appear to be a target as Pb exposure results in suppression of testosterone synthesis. However, the effect of Pb toxicity on Leydig cells and its molecular mechanism remained less investigated. And the role of the mitochondria pathway in Pb-induced Leydig cells apoptosis in unknown.
A male germ cell assay and supporting somatic cells: its application for the detection of phase specificity of genotoxins in vitro
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Khaled Habas, Martin H. Brinkworth, Diana Anderson
Leydig cells, also known as interstitial cells of Leydig, regulate development of spermatogenesis in seminiferous tubules through secretion of growth factors and hormones which are responsible for steroidogenesis and male germ cell development (Heinrich and DeFalco 2019). In a rodent, Leydig cells are formed as functionally and morphologically different generations. The fetal Leydig cell as the first generation develops in utero from undifferentiated stem Leydig cells (SLCs) (Dong et al. 2007). Leydig cells are primary endocrine cells that produce androgens in men. Increased glucocorticoid levels were found to be associated with decreased serum testosterone (T) levels and dysfunctional male reproduction (Monder et al. 1994; Smals, Kloppenborg, and Benraad 1977).
Citrate ester substitutes for di-2-ethylhexyl phthalate: In vivo reproductive and in vitro cytotoxicity assessments
Published in Journal of Toxicology and Environmental Health, Part A, 2020
Chi Rim Sung, Hyeon Gyu Kang, Ji Young Hong, Seung Jun Kwack
In addition, an in vitro cytotoxicity assessment was conducted using methyl tetrazolium (MTT) assays comparing the viability of mouse Leydig cell (TM3 cells), which are responsible for male hormone synthesis, and of mouse fibroblasts (NIH-3T3 cells), which are non-reproductive cells. Leydig cells within the testicles are responsible for the production of testosterone, a steroid hormone maintaining male reproductive ability. DEHP suppresses testosterone production in Leydig cells by disrupting the activation of proteins and enzymes involved in testosterone synthesis from cholesterol (Svechnikov et al. 2010). Thus, the aim was to identify any potential adverse effects of DEHP substitutes on Leydig cells as evidenced cytotoxicity assessment.