Organization and Activation of Sex Hormones - Essay Example

Organization and Activation of Sex Hormones One of the functions of the endocrine system is the production of sex hormones. Sex hormones play crucial roles that attribute for the differences between males and females physically and behaviorally. There are distinct hormones for each sex that perform both organizational and activating functions. Organizational effects are responsible for the permanent anatomical and organ differences between men and women. On the other hand, activation effects are responsible for behavioral and short-term effects in men and women in the later stages of life. Studies reveal that sex hormones have the potential of causing abnormalities in sexual development. Researchers have relied on the concept of the organizational-activational theory providing explanations of the inherent differences between males and females. The theory’s credibility has given it substance of relevance over time. The effect of sex hormones sets in during the fetal stages. The combination of the sex chromosomes during fertilization determines the sex of the fetus that results. Since females have only X sex chromosomes, the sex of the fetus solely depends on the probability of the male sperm possessing either X or Y chromosome. In the case where it is Y, the combination forms XY, a condition that translates to the production male sex hormones. X chromosomes in the sperm lead to XX resulting to female sex hormones. Female sex hormones include estrogen and progesterone while testosterone is the most crucial male hormone. Researchers trying to unravel the mystery behind the effects of sex hormones have indulged in demystifying the numerous theories that surround the functioning of sex hormones. It has become clear that the organizational effects determine whether the embryo develops male or female internal organs (Arnold, 2009). Organizational Effects As a male fetus develops, it undergoes a process that enables it to adopt masculine features. This process takes place under the influence of testosterone. The forming testes release substantial amounts of the hormone. Pioneers of research in this field had proposed that the effects of testosterone came alongside a decline of feminine hormones. Time has allowed the availability of detailed more subjective research that has served to prove these claims wrong. It has become evident that the organizational process of the male fetus does not occur alongside the decline of feminine characteristics (Arnold, 2009). Other researchers described the effects of sex hormones in organization as permanent. This inference resulted from the fact that the organizational effects were evident during the last trimester of the gestation period. Research has ascertained that testosterone administered during the fetal stage can prevail until puberty. On the other hand, these researchers described the activating effects of sex hormones as short-lived. Activating effects of sex hormones comprise of sexual function of adults in both male and female. In addition, the changes in behavior evident in puberty are the result of activation by sex hormones. In addition, the numerous physical changes fall under the activation category. In addition, these researchers highlighted that the organizational period involved an intensive process of differentiation. According to them, differentiation reflected the organizational effects of sex hormones produced during the fetal stages. In the prenatal period, the sex hormones produced lead to the organization of the gonadal hormone in a definite way that makes them subject to activation in adulthood. During adulthood, these hormones result to activation of the gonadal tissues. However, the effects of the hormones extend to the activation of neural tissues involved in sexual stimulation. Moreover, the initial prediction of the effects of sex hormones indicated that testosterone had the capacity of exerting a form of influence on the brain. The findings and description of Phoenix and his colleagues of the organization and activation theory of sex hormones have sparked numerous probes to ascertain their findings. Their conclusion has given other researchers the direction to their studies and experiment. Some studies have focused on the prenatal hormone effects as others unravel the activation of hormones in adulthood. One fascinating finding made by Phoenix and his colleagues is the assertion that both males and females possess the capacity to project behavior that is characteristic of the opposite sex. Critiques of the organizational –activation theory have taken this translate to an incomplete process of organization. Researchers define the capacity as limited and of unequal in the gonadal and neural tissues. However, other experts have asserted that the expression of this capacity has its limitations and does not come easily. This argument is more logical and realistic especially in mammals. On the other hand, it serves to explain the current prevalence of homosexuality. From the findings and conclusions of Phoenix and his colleagues as described by Arnold (2009), it becomes rational to seek a definition of the processes that take pace during puberty. Some researchers have sought to establish whether the developmental changes involving secondary sexual characteristics fall under the category of activation or under the long-term effects of organization. It is evident that the changes that occur during puberty are permanent and this justifies the concern of some scientists whether a second level of differentiation is responsible. These issues have determined the direction of recent research. The studies that followed Phoenix and his colleagues have succeeded in proving substantial evidence supporting majority of their findings. In the 1970s, research revealed that there are changes in morphology in brain regions a fact that augments the assertions of the preceding research. Although the differences are not as pronounced as those inherent in the gonadal organs, these researchers provided a new understanding the level of organization that occurs during the prenatal periods. These morphological differences in the brain regions account for the diverse reactions of males and females during copulation, courtship, and ovulation. The organizational-activation framework coined by Phoenix and his colleagues in 1959 serves to offer credible explanations on the organization of the brain as a substrate for sex hormones (Micevych, & Hammer, 2005). Other researchers have suggested that there is a need to develop a cellular and molecular description of the organization and activation in the brain (Kling, 2010). An understanding of the organizational effects on the brain offers reliable explanation for the resulting permanence of the brain as a potential substrate for the sex steroids. Through the development of such an understanding, it has proved possible to describe why the brain undergoes permanent changes during the prenatal period. Other augmenting findings include the description of the presence of multiple sites of action in the brain, a fact that broadens the understanding of the action of sex steroids. In addition, the capacity of the brain to release other steroids has its implications on the action of hormones. Abnormal Sexual Development Abnormal sexual development forms an issue of interest for other scientists who are seeking to unravel the contribution of sex hormones in their occurrence. The organizational effects of sex hormones accounts for the differentiation of gonads in males and females (Rathus, 2011). Normal development in a female leads to the formation of a uterus, vagina, labia, and ovaries. In males, the development of penis and testes reflect normal sexual development. Normal development is the result of appropriate organization during the prenatal period. However, any abnormality in the action of sex steroids in the prenatal period translates to inappropriate differentiation of the gonadal organs. Abnormal sexual development may depict itself in both males and females. There are reports of females born without a uterus. In other cases, a female may possess organs typical in males. Other abnormalities in females involve the absence of menstruation, which is an essential function of sex hormones. In some cases, cells of either the male may portray resistance to the effect of sex hormones. In females, abnormality may result from the disorders that lead to high product ion of male androgens, surpassing the effect of feminine sex steroids (Maggi, 2012). It is evident that sex hormones have two categories of effects. The organizational-activation theory developed by Phoenix and his colleagues reveals distinct the two categories. The organizational effects are very evident in the prenatal period as described by multiple researchers. These effects cause permanent differentiation of the fetal sex organ into either male or female. The activation effects result later in puberty and adulthood. The theory has received evidential support from other researchers over time augmenting the initial findings. However, sex hormones may also account for some abnormal sexual development. References Arnold, P. (2009). “The organizational-activational hypothesis as the foundation for a unified theory of sexual differentiation of all mammalian tissues”. Hormones and Behavior 55(2009), 570-578. Klinge, G. T. (2010). Sex and gender in biomedicine: Theories, methodologies, results. Göttingen: Univ.-Verl. Göttingen. Maggi, M. (2012). Hormonal therapy for male sexual dysfunction. Chichester, West Sussex, UK: Wiley-Blackwell. Micevych, P. E., & Hammer, R. P. (2005). Neurobiological effects of sex steroid hormones. Cambridge, UK: Cambridge University Press. Rathus, S. A. (2011). Psych. Belmont, Calif: Wadsworth. Read More