Spermatogenesis is a complex and well-orchestrated process, in which Spermatogonial Stem Cells (SSCs) divide and differentiate to produce unlimited numbers of mature spermatozoa. This process is continuous throughout the adult life in most mammals. The seminiferous epithelium consists of only one somatic cell type, sertoli cell [1] and many different germ cell types [2]. Sertoli cells play a nu...

In this review, we aim to examine the effect of extrinsic and intrinsic factors on spermatogenesis process taking into account a complex signaling pathway. Primarily, it is suggested that retinoic acid (RA) has a vital function in spermatogenesis process and it is considered to be essential for completion of spermatogonia into mature spermatozoa. In the present review, the key effects of retino...

Irradiation interrupts spermatogenesis and causes prolonged sterility in male mammals. Hormonal suppression treatment with gonadotropin-releasing hormone (GnRH) analogues has restored spermatogenesis in irradiated rats, but similar attempts were unsuccessful in irradiated mice, monkeys, and humans. In this study, we tested a stronger hormonal suppression regimen (the GnRH antagonist, acyline, a...

Spermatogenesis is composed of three distinctive phases, which include self-renewal of spermatogonia via mitosis, spermatocytes undergoing meiosis I/II and post-meiotic development of haploid spermatids via spermiogenesis. Spermatogenesis also involves condensation of chromatin in the spermatid head before transformation of spermatids to spermatozoa. Epigenetic regulation refers to changes of h...

The first step in established spermatogenesis is the production of progenitor cells by the stem cell population. The progenitor cells (undifferentiated A spermatogonia) expand in number via the formation of syncytial chains by mitosis. The mechanism by which these progenitor cells commit to meiosis and spermatogenesis is tightly controlled and results in complex morphological organization all o...

Stem cells give rise to differentiated cell types but also preserve their undifferentiated state through cell self-renewal. With the use of transgenic mice, we found that the RNA-binding protein NANOS2 is essential for maintaining spermatogonial stem cells. Lineage-tracing analyses revealed that undifferentiated spermatogonia expressing Nanos2 self-renew and generate the entire spermatogenic ce...

INTRODUCTION Male fertility requires continual spermatogenesis, a process dependent on activities of an undifferentiated spermatogonial population composed of spermatogonial stem cells (SSCs) and transient amplifying progenitor spermatogonia (de Rooij and Russell, 2000; Oatley and Brinster, 2012). Self-renewal of SSCs maintains a constant pool from which progenitors will arise and amplify in nu...

BACKGROUND The lifesaving chemotherapy and radiation treatments that allow patients to survive cancer can also result in a lifetime of side-effects, including male infertility. Infertility in male cancer survivors is thought to primarily result from killing of the spermatogonial stem cells (SSCs) responsible for producing spermatozoa since SSCs turn over slowly and are thereby sensitive to anti...

A 400 bp fragment of the spermatogonia-specific Stra8 locus was sufficient to direct gene expression to the germinal stem cells in transgenic mice. A fractionation procedure was devised, based on immunomagnetic sorting of cells in which the promoter drives the expression of a surface functionally neutral protein tag. The purified cells expressed the known molecular markers of spermatogonia Rbm,...