The man in the flashy sports car had been tailgating me for the past five miles. When he finally had the opportunity to pass me, he accelerated and decided to flip me the bird as he zoomed past me. I wondered what was making him so aggressive, and immediately thought about the steroid hormone testosterone and its role in aggression. Testosterone, like androgens such as DHEA, and DHT, is a necessary hormone for the expression and maintenance of male primary and secondary sexual characteristics (Nelson and Kriegsfield, 2017). Though testosterone is the primary male sexual hormone, it is also present in females at very low levels (Celec et al., 2015). The synthesis of testosterone occurs mainly in the Leydig cells of the testes in males, whereas
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Through incredibly complex mechanisms, testosterone can be synthesized and act as a neurosteroid in certain areas of the brain (see review Mellon et al., 2001). Testosterone and its derivatives, produced in the fetus, neonatally, and throughout sexual maturation, are responsible for the masculinization of the male brain (see review Simerly, 2002). Moreover, differences in androgen and estrogen levels in male and female brain lead to the appropriate development of male-typical and female-typical neural circuitry (see review Simerly, 2002). Due to these differences, it is to be expected that manipulation of testosterone levels would have significant effects on the expression of certain behaviors in males and females. Numerous studies have been conducted to investigate the relationship between testosterone and aggressive behaviors. In addition, the modulating factors of this relationship have been extensively studied. Aggressive behaviors, such as biting attacks, are often expressed in response to threatening stimuli, as well as to obtain and maintain resources and social status (de Boer, 2018). It is important to emphasize that aggressive behaviors are the means to an end for many species, but can be well-controlled and are context
Through incredibly complex mechanisms, testosterone can be synthesized and act as a neurosteroid in certain areas of the brain (see review Mellon et al., 2001). Testosterone and its derivatives, produced in the fetus, neonatally, and throughout sexual maturation, are responsible for the masculinization of the male brain (see review Simerly, 2002). Moreover, differences in androgen and estrogen levels in male and female brain lead to the appropriate development of male-typical and female-typical neural circuitry (see review Simerly, 2002). Due to these differences, it is to be expected that manipulation of testosterone levels would have significant effects on the expression of certain behaviors in males and females. Numerous studies have been conducted to investigate the relationship between testosterone and aggressive behaviors. In addition, the modulating factors of this relationship have been extensively studied. Aggressive behaviors, such as biting attacks, are often expressed in response to threatening stimuli, as well as to obtain and maintain resources and social status (de Boer, 2018). It is important to emphasize that aggressive behaviors are the means to an end for many species, but can be well-controlled and are context