Natural Estrogen

Now that we know how bad environmental estrogens are, it is important to ask the question, “why?” In order for one to be able to comprehend the toll these estrogens play on one’s body, a fundamental understanding of the natural estrogen pathway in the body is necessary.

The majority of physiological functions in our body occur via negative feedback loops. Estrogen and testosterone pathways are no exception to this rule. The main structures involved in the feedback loop that is affected by foreign estrogens are they hypothalamus, hypophysis (neurophypophysis and adenohypophysis) and the cells of the gonads (ovaries and testes). The hypothalamus forms the floor and lower walls of the brain and it functions in regulation of body temperature, thirst, hunger, sleep, response to stress, and aggressive and sexual behaviors [3]. The pituitary gland, or hypophysis, contains two subdivisions, the neurohypophysis and the adenohypophysis. The hypophysis synthesizes and secretes hormones into the bloodstream [3]. Without this very important gland, our reproductive system would not function. The hormones secreted from the hypophysis act on the gonads and causes them to secrete estrogen, progesterone, or testosterone.

The hypothalamus secretes Gonadotropin Releasing Hormone (GnRH), which acts on the adenohypophysis and causes it to secrete Luteinizing Hormone (LH) or Follicle-Stimulating Hormone (FSH). LH and FSH act on the cells of the gonads and cause them to secrete estrogen, progesterone or testosterone [3]. It is necessary to have a mechanism to control the release of all of these hormones. This is where the negative feedback loop comes in to play. Excessive amounts of estrogen or testosterone will signal to the hypothalamus to stop secreting GnRH and the adenohypophysis to stop secreting LH and FSH. No GnRH, LH, and FSH means no estrogen and no testosterone.

The picture above helps to summarize the negative feedback loop. Steroidogenesis, the production of testosterone and estrogen, is controlled by the concentrations of the hormones themselves. Small concentrations signal to the hypothalamus to secrete GnRH, which signals the pituitary gland to secrete LH and/or FSH, which signals to the gonads to produce estrogen and testosterone. The body cannot distinguish between natural estrogen and xenoestrogen and therefore, any synthetic estrogen could bind to estrogen receptors within the body and create a plethora of issues for the individual. These issues, breast cancer, infertility, estrogen dominance, etc., are discussed in detail in the following pages.

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