Module 3S2 Chemistry of Reproduction
Lesson 2.3.4S2
Lesson 4—Effects of Reproductive Hormones
Get Focused
Without proper hormonal control of the reproductive system, events like ovulation and sperm production cannot take place; this results in the lack of fertilization, and the failure to ensure continuation of the species. Normal hormone control may be altered knowingly, by taking hormones to enhance or prevent pregnancy and to treat disorders. Hormone control may also be altered unknowingly through the effects of endocrine disruptors.
Male and female sex hormones are not only used to promote or avoid conceiving a child, but can also be used to treat other disorders. When the normal release of reproductive hormones is changed, the release of FSH and LH can be affected, which in turn reduces the development of egg and sperm. Progestin, synthetic progesterone, was the first chemical used as a female oral contraceptive, known as ‘the pill’. Varying quantities of estrogen and progesterone are used in today’s contraception pills.
Other conditions can also be treated with sex hormones. In the initial treatments using chemotherapy (the chemical treatment of disease), prostate cancer was treated with female sex hormones. Many types of cancer are now treated with female and male sex hormones. Menopause, andropause, impotence, low sperm count, arthritis and osteoporosis can be treated through the use of sex hormones.
Endocrine disruptors are synthetic or naturally occurring substances that interfere with the functioning of the body’s normal production of hormones. The endocrine disruptors can be absorbed into the body through contaminated water, food or air. Their effects can halt or stimulate normal hormone levels, or they may change how hormones travel in the body, affecting what the hormone controls. Some known human endocrine disruptors are dioxin, PCB’s, DDT and diethylstilbesterol (a drug known as DES). You may wonder if endocrine disruptors really affect humans. “In the 1950s and 1960s, pregnant women were prescribed diethylstilbestrol (DES), a synthetic estrogen, to prevent miscarriages. Not only did DES fail to prevent miscarriages, but it also caused health problems for many of these women's children. In 1971, doctors began reporting high rates of unusual vaginal cancers in teenage girls. Investigations of the girls' environmental exposures traced the problem to their mothers' use of DES. The girls also suffered birth defects of the uterus and ovaries, and immune system suppression.”
Exposure to endocrine disruptors during development can have permanent effects on an organism. There is further evidence that endocrine disruptors may have consequences for many generations, not just for the immediate person or organism.
Remembering back to the Fertility Case Study, both Sam & Sarah, had hormone issues with their infertility problem. Sara used oral contraceptives for a long time prior to wanting to start a family, and Sam had misused anabolic steroids for many years.
Understanding how normal reproductive hormones control and affect the body can help you understand how these reproductive hormones are used to promote or reduce conception potential, to treat diseases, and how they are influenced by endocrine disruptors.
Keep the following focusing question in mind as you work through this lesson:
- What are the various effects of reproductive hormones?
This lesson should take approximately 40 minutes.
Module 3: Section 2—Lesson 4 Assignment
In addition to the lesson work you complete for your course folder you will complete questions on endocrine disruptors in the environment for assessment. You are not required to hand an assignment in but please read the material presented.
Here is a tutorial video for this lesson that you can watch if it suits your learning style. Bio30 2.3.4S2 Contraception