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Impact of evolution on human thought Testosterone - Реферат

It is a good point, but what about evidences suggesting that men after taking testosterone injection find themselves more aggression than normally. The article "The He Hormone" by Andrew Sullivan brings a good example when a man after taking testosterone shot could not control his increased aggressiveness and "had nearly gotten into the first public brawl of his life."

"Soon after I inject myself with testosterone I feel a deep surge of energy. My attention span shortens. My wit is quicker, my mind is faster, but my judgement is more impulsive."

Several other studies suggest that individuals with winning attitudes have higher testosterone levels, at least for a short period of time, than those without such an attitude. One group of researchers, for example, measured testosterone levels in six college tennis players and found that testosterone levels began to rise in all of them before their matches, apparently in anticipation of competition. The big surprise came after the fact: the testosterone levels of those who won their matches remained high, while the testosterone levels of those who lost diminished.

A second group of researchers, at North Dakota State University in Fargo, undertook even further step by trying to figure out if it was the competition itself, or the mood produced by winning, that caused the rise in testosterone. In their experiment, male college students either won or lost $5 through a series of coin tosses. The task removed all elements of skill or competition; blind luck determined winners and losers. After the tosses had been finished, the researchers measured the saliva of participants for changes in their testosterone levels. Those who won money experienced a more positive mood and a rise in "test"; those who lost whose a decrease in the later. The result suggested that the acts of winning, rather than the nature of the competition or the skill involved, improve mood and produces an increase in testosterone levels. This experiment obviously supports Robert's Saporky statement that testosterone level changes with external factors.

Two more recent studies by a single group of researchers went further to find out if one has to directly participate in competing in order to experience increase in testosterone level. In the first study, the researchers measured the salivary testosterone levels of fans who attended a college basketball game. In another, they took the same measurement of a group who watched a World Cup soccer match on television. In each study, testosterone levels were taken before and after the game. In both experiments, those fans whose team had won experienced a surge in their testosterone levels, while those fans whose team had lost showed a drop.

The result was very surprising. Even the fans are not directly involved in the competition, the their testosterone levels change in accordance with whether their team is losing or winning. The supervisor of the researches, a doctoral candidate in education psychology at the University of Utah in Salt Lake City, makes a comment on the researches notes: "Fans do not have much to do with outcome: there are more like voyeurs to the team's experience of competition." Nonetheless, experiencing victory even vicariously apparently has very real effect on a person's hormone levels.

Testosterone level is not only different among individuals, but it changes within one organism one intraday basis. Testosterone level can vary by up to fifty percent during one day. In the mornings it tends to be higher than in the evenings. This is another reason why people feel fresh in the mornings. During the day one might experience ups and downs of testosterone level induced by winning mood effect. These up and downs do not have effect on physical development of the individual ("The Testosterone Syndrome," Eugene Shippen, William Fryer).

Sensitivity to the changes in the testosterone levels is not very researched subject. It is noticed that different individuals experience different effects after having the same amount of testosterone injected. The genetically determined differences in the numbers of testosterone receptors may be one factor.

Besides stimulating growth of bones, body mass, facial hair, change in voice, testosterone might be a possible reason of illnesses. In the report by Paule A. Lotufo, Joann E. Manson, Alexandersen P, Haarbo J, Christiansen C., on male pattern baldness and coronary heart disease, the authors conclude that "vertex pattern baldness appears to be a marker for increased risk if coronary heart disease. They state that testosterone may provide a "plausible explanation for an association between baldness and coronary heart disease." The reference cited is a study that shows elevated testosterone levels in men with prostate cancer and baldness; however, these were no measured testosterone concentrations in the data presented. Dr. Brian L.G. Morgan and Roberta Morgan, in their book "Hormones," are tying to link high testosterone level with coronary heart disease. They bring into attention the fact that in general, since women have lower testosterone levels than men, according to available poll of data, they live longer lives. "Equal numbers for both sexes are around by age thirty, and only 70 percent of men reach age sixty-five, where as 84 percent of women do."

On the contrary recent results from the Telecom Study showed that decreased testosterone levels were associated with increased cardiovascular risk factors in otherwise healthy men.

Eugene Shippen and William Fryer, in their book "Testosterone syndrome," agree with the opinion that low level of testosterone are more associated with increased cardiovascular risk factors, rather than all the way around.

"The fundamental fact is this: a clear and ever-increasing majority of medical studies report an association between high testosterone and low cardiovascular disease in men. This is not a coincidental association, since when testosterone is diminished well-accepted risk factors increase, and when testosterone is administered in appropriate doses most of the major risk factors for heart disease diminish. Moreover, in the majority of patients, symptoms and objective EKG measurements improve. These studies are confirming the results I have been getting with patients for years. Men prosper health wise and live longer when their testosterone levels are normal. Heart problems, in particular, are more easily controlled (The Testosterone Syndromes, pp. 81)."

With growing old, men begin experiencing erective problems and losing sexual interest. These problems are caused by diminishment in testosterone level. Facts reveal that men who are taking testosterone, in any form, experience surge of sexual interest, and overall enhancement in physical strength. Eugene Shippen, and William Fryer, in their book "The Testosterone Syndrome," relate diminishing sexual interest to a sign of future heart disease and diabetes, conditions common in the male menopause ("The Testosterone Syndrome," pp. 59)

At the end of this research, I would like to notice and bring example of the fact that majority of scientific world hold opinion that artificial testosterone if correctly applied can bring much of good to the human kind, especially to elderly.

"Standford R. is seventy-four years old now, but he has had heart problems since the early 1970s. It did not make life easy for him. He is an athletic man who likes to hunt, fish on the river, and walk in the woods. By the time Standford together with his chest pains, got into the 1980s, it was time for a quintuple bypass. The chest pains started up again in a few years later. His chest pains went away, his energy returned and when he is not walking over the hills and fields and hunting in the woods, Standford makes love. Sometimes twice a day ("The Testosterone syndrome," pp79).

Conclusion

As can be concluded from all researches discussed above change in testosterone level triggers changes in behavioral pattern, and environmental change followed by change in behavioral pattern triggers change in testosterone level.

The arguments in scientific world regarding testosterone and their role in human anatomy are not over yet. The subject is hard to explore, because experiments that has to be done in order to find right answers are not considered to be ethical on humans. The scientific world has no choice, but to use random historical facts to come to the answers. However, the fact the testosterone play a huge role in human development and behavior is not argued by any more.

Reference:

  1. "The Testosterone Syndrome"; Eugene Shippen, M.D. and William Fryer, M. Evans and Company, Inc., 1998

  1. "Hormones; Molecular Messenger"; John K. Young, Franklin Watts, 1994

  1. "The Trouble with Testosterone and other essays on the biology of the human predicament"; Robert M. Sapolsky, Scribner, 1997

  1. "The Hormone of Desire; The Truth about sexuality, menopause, and testosterone"; Susan Rako, M.D., Harmony Books, 1996

  1. "Never Too Buff"; John Cloud

  1. "The He Hormone"; Andrew Sullivan

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