It is possible that testosterone signaling that increases dramatically in stages VII–VIII of the cycle may be responsible for the remodeling of Sertoli-germ cell adhesion complexes that occurs during these stages when round spermatids begin to elongate. In these studies, testosterone stimulation could only increase the attachment of germ cells to Sertoli cells expressing wild type AR or mutated AR that can stimulate the non-classical pathway.40 These findings suggest that testosterone can act via the activation of Src and ERK kinases to facilitate Sertoli-germ cell attachment. However, the addition of inhibitors of Src or ERK kinase reduced germ cell attachment below basal levels.40 Additional studies were performed in which AR-defective Sertoli cells were infected with adenovirus constructs expressing wild type AR or AR mutants that selectively activated only the classical pathway or the nonclassical pathway. The activation of Src and Erk kinases by non-classical testosterone signaling was found to alter processes that are critical to maintain spermatogenesis.
In this way the level of testosterone in the male’s body is kept within a relatively narrow range. In this case the testosterone signals the hypothalamus to decrease the amount of GRH produced, therefore reducing the secretion of LH and FSH, and, in turn, decreasing testosterone production. The production of testosterone by the testes is regulated by a negative feedback loop (Figure 4). Testosterone then circulates through the bloodstream and has effects all over the body and the brain (See table 1 for some effects of testosterone). The organs and structures described on the previous page need to work together under hormonal signaling to release semen with mature and motile sperm out of the penis. In conclusion, a systems biology approach integrating these multifactorial interactions will likely provide new insights into male reproductive endocrinology. Chromosome conformation capture assays can analyze changes in genome interactions, contributing to the elucidation of mechanisms by which nuclear receptors bind to chromatin and regulate gene expression (Chakraborty et al., 2021).
The FSH receptor (FSHR), responsible for binding FSH, is exclusively expressed on the cell membrane of Sertoli cells. The activation of Src and FAK is essential to support sperm cell adhesion and sperm release, and both can be phosphorylated during non-classical androgen signaling activation 54,63,64. Additionally, the role of androgen signaling also includes maintaining the Sertoli cell–spermatid adhesion to prevent spermatid shedding from the epithelium and regulating the release of sperm. Testosterone also promotes the phagocytic clearance of apoptotic germ cells by Sertoli cells, possibly by increasing the expression of miR-471-5p and Elmo1 59,60,61. Furthermore, reduced testosterone levels elevate ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) expression in spermatogonia, thereby promoting the ubiquitination of the apoptosis factor p53 .
Thus the link between testosterone and aggression and violence is due to these being rewarded with social status. This could explain why some studies find a link between testosterone and pro-social behaviour, if pro-social behaviour is rewarded with social status. Rats who were given anabolic steroids that increase testosterone were also more physically aggressive to provocation as a result of "threat sensitivity". One study found that administering testosterone increased verbal aggression in some participants. The Annals of the New York Academy of Sciences has found that the use of anabolic steroids (which increases testosterone) among teenagers is correlated with increased likelihood of using violence. One study proposed that natural selection may have caused men to be more sensitive to situations in which their status is challenged, and that testosterone is the key factor that causes these situations to spark into aggression.
The attainment of proper masculinization after birth hinges on the adequate development of testicular somatic and germ cells during the fetal period, particularly during a pivotal phase termed the masculinization programming window. Interestingly, treatment with OT has been found to increase the expression of proliferating cell nuclear antigen (PCNA) and B cell lymphoma 2 (Bcl-2) proteins in the testis, suggesting that OT may play an important role in the proliferation, survival, and death of germ cells . OT is a neurohormone stored and secreted by the posterior pituitary gland and has been found to be present in the male reproductive tract .
Building awareness of how your body responds to different nutrients and foods across your cycle creates the foundation for hormonal health that feels sustainable and genuinely supported rather than fought against. This is not about perfection or extreme restriction; it is about working with your female physiology in practical, sustainable ways that accumulate into genuinely improved health and wellbeing across every phase of your cycle. The relationship between blood sugar stability and hormonal health is direct and measurable. Measurement of free testosterone and oestradiol in women using liquid chromatography-tandem mass spectrometry. This assessment helps identify which aspects of your hormonal health might most benefit from targeted testing and intervention. Building awareness of how your body responds to different foods and the timing of your cycle creates a foundation for stable blood sugar and hormonal health. Beyond direct hormonal effects, blood sugar dysregulation drives systemic inflammation.
However, its influence extends far beyond the realm of reproductive health, impacting various physiological processes in both males and females. Testosterone is a steroid hormone that plays a crucial role in the development and maintenance of male reproductive tissues and secondary sexual characteristics. Agnathans (jawless vertebrates) such as lampreys do not produce testosterone but instead use androstenedione as a male sex hormone. In women, mean levels of total testosterone have been reported to be 32.6 ng/dL.
The existence of steroidogenesis and steroid signaling within immune cells presents new possibilities for understanding how immune cells communicate and shape the physiology of immune responses, as well as how they become dysregulated in disease states. Psychological stress, which increases systemic glucocorticoid levels, impaired Sertoli cell function in adult rats (Medubi et al., 2021). Testosterone production surged after adrenalectomy, which glucocorticoid replacement prevented (Whirledge and Cidlowski, 2017), revealing an interplay between glucocorticoid and testosterone levels. A 50% reduction of GR in Leydig cells using AAV9-Cre disrupted steroidogenesis (Gannon et al., 2022), suggesting a role for GR in Leydig cell function.