Effects of Testosterone on the Human Body

Hormones are a chemical substance which is secreted from the endocrine gland into our blood to target specific areas for action. These hormones are what occurs in both woman and men, but each sex needs different amounts, for different areas of the body to cause different effects. Testosterone is thought of as a male hormone in men as it has long been linked to different male behaviours and is present in a male before and after birth effecting behaviour and development. (Carré & Archer, 2018).

Testosterone has an effect even from inside the mother’s womb as it develops the sex of a male’s organs at seven weeks old which also influences the brain making the hypothalamus more enlarged in volume. (Vousden et al., 2018).

Testosterone has advantages to a male’s physical state before and after as not only does it form a male’s organs in conception but also increases at puberty in later development. Testosterone allows the testes to produce and grow, producing regular sperm with levels of testosterone increasing right through puberty. This is shown in a male’s voice, by becoming deeper.  Also, growth in pubic hair and muscle density to grow strong and form allowing manly features to show and along with this comes an increase in sexual desires and competitiveness.

In male testosterone increases neurotransmitters which help tissue to grow, which in turn testosterone increases levels of hormone growth, making exercise more likely to build muscle. This is known as Gonadal hormones and as it helps males bulk where females do not bulk as easily. The gonadal hormone is what controls the reproductive functions in testosterone and oestrogen and identifies a woman from a man biologically. (Comer, Gould, & Furnham, n.d.).

While testosterone has its advantages, it also has disadvantages as men with low levels of testosterone may experience erectile dysfunction. A person can feel a loss of confidence, with no sex drive and feel low on energy levels which results in weight gain and sweating of the body as the body is unable to regulate its body temperature. (Yassin & Saad, 2008).

The body temperature stays regulated due to the anterior pituitary gland (frontal gland) as this is under the control of hormones secreted by the hypothalamus (brain). Hormones released from the hypothalamus is sent down the axon, which is then connected to the pituitary gland, then carried to the anterior gland which release tropic hormones. These hormones help keep the body in a regular state. (Jannini, Screponi, Pepe, Giudice, & Benvenga, 1999).

In a response to stress, the hypothalamus in the brain gives a signal to the adrenal glands which then secrete glucocorticoids and cortisol. If levels of cortisol in the blood remain high from constant stress, overuse can result in lower ability to regulate cortisol so lower levels are then produced through overuse due to damage to the hippocampus. This can stop our fight or flight mode and immune response or metabolism, causing aggressive behaviour and stress from the breakdown of several areas. (Carré & Archer, 2018).

There are many arguments over the brains lateralization and what functions take over from the effect of testosterone from male behaviours such as aggression and visuospatial. In a man the hypothalamus contains a cluster of large cells which is known as the sexual dimorphic nucleus, when compared in size to a female’s brain, the males appear to be much larger in size.

As research has already shown, the brain has two sides, left and right. The left for language and right for spatial and non-verbal tasks.

Research carried out by young 1996, (Baxter et al., n.d.) using MRI scans to monitor the brain during language tasks was done to see if there is evidence of reasons to why the male has a larger SDN. This showed that woman used both left and right hemispheres, whilst the male used only the left side. Evidence showed that a male’s brain was influenced by testosterone by working more independently on one side compared to the female’s brain of both sides which shows testosterone can influence lateralization of a man’s brain resulting in the size difference on the SND.  

Research was carried out (Henley, Nunez, & Clemens, 2010) with rats to see the effect of testosterone on the SDN showed similar similarities in the size difference in the brain. This was done by injecting female rats during their early stages of development. Not only did they show aggressive and experimental behaviour later in life, but also young found the size in the SND in males to be larger compared to the females SND. This showed a repeated pattern carried out by Baxter in 2003. 

As the study was carried out in a lab by injecting the rats with injections the rats received a higher dosage than what a human would compared to what a human who would receive on a daily basis at steady and natural pace when the body needs it so findings of this where not seen as been as generalizable compared to that in a naturalistic environment which Baxter carried out. Also, another main factor is that animals and humans do not have the same brain structure to start with making the research and validity uncertain and the main factor raised was if it was it right to use animals in such a cruel way.

In the evolutionary approach to gender, it believes that gender role came from our ancestors through needs of survival to reproduce from the environment. So, men hunt, and woman stay at home to nurture the children, meaning genes are coded. The biological approach to gender argues that nature and nurture both play roles in development. The suggest that gender is determined by certain events from exposure to prenatal hormones and postnatal labelling from what gender they are. (Miller, 2016).

Regardless of nature or nurture or testosterone in pre-stages, are we as a modern society doomed to fail as woman, men been more competitive, whether it is an evolutionary one, leaving our genes to play fate subject to a hormone or a biological one coming from social labelling after genitals, regardless both gender play crucial roles in future development of a child as we have seen proof of this through evolving in numbers. 

References

• Baxter, L. C., Saykin, A. J., Flashman, L. A., Johnson, S. C., Guerin, S. J., Babcock, D. R., & Wishart, H. A. (n.d.). Sex differences in semantic language processing: A functional MRI study. Retrieved from www.elsevier.com/locate/b&l
• Carré, J. M., & Archer, J. (2018). Testosterone and human behavior: the role of individual and contextual variables. Current Opinion in Psychology, 19, 149–153. https://doi.org/10.1016/j.copsyc.2017.03.021
• Comer, R. J., Gould, E., & Furnham, A. (n.d.). Psychology. Retrieved from https://catalogue.sunderland.ac.uk/items/385593?query=psychology+ronald+comer&resultsUri=items%3Fquery%3Dpsychology%2Bronald%2Bcomer
• Henley, C. L., Nunez, A. A., & Clemens, L. G. (2010). Exogenous androgen during development alters adult partner preference and mating behavior in gonadally intact male rats. Hormones and Behavior, 57, 488–495. https://doi.org/10.1016/j.yhbeh.2010.02.007
• Jannini, E. A., Screponi, E., Pepe, M., Giudice, F. L. O., & Benvenga, S. (1999). Lack of sexual activity from erectile dysfunction is associated with a reversible reduction in serum testosterone, 392, 385–392.
• Miller, C. F. (2016). Gender Development, Theories of. The Wiley Blackwell Encyclopedia of Gender and Sexuality Studies, (April), 1–6. https://doi.org/10.1002/9781118663219.wbegss590
• Vousden, D. A., Corre, C., Spring, S., Qiu, L. R., Metcalf, A., Cox, E., … Palmert, M. R. (2018). Impact of X/Y genes and sex hormones on mouse neuroanatomy. NeuroImage, 173, 551–563. https://doi.org/10.1016/j.neuroimage.2018.02.051
• Yassin, A. A., & Saad, F. (2008). Testosterone and Erectile Dysfunction. Journal of Andrology, 29(6), 593–604. https://doi.org/10.2164/jandrol.107.004630