Hormones and Sexuality

1. Hormones and Sexuality The Endocrine System The Menstrual Cycle Length of the Menstrual Cycle Menstrual Synchrony and Pheromones Attitudes About Menstruation: Historical Perspectives Attitudes About Menstruation Today Menstrual Problems Regulation of Male Hormones Hormones and Sexual Desire

2. The Endocrine System • Hormones play a crucial role in both men and women. They are important for growth, metabolism, water retention, reaction to stress, and many other functions. • Hormones are chemical substances that are released into our bloodstream by ductless glands. They are carried in the blood to other parts of the body where they exert their effects. Hormones released by one gland often cause another gland to release its own hormones. This network of ductless glands is called the endocrine system.

3. The testicles and the ovaries are part of the endocrine system. The testicles manufacture and release testosterone, and the ovaries produce progesterone and estrogen. • The pituitary gland releases eight different hormones into the bloodstream. Two of these have their effect on the ovaries and testicles, and are thus called gonadotropins. • In women, follicle-stimulating hormone stimulates the maturation of a follicle in the ovaries.

4. A second pituitary gonadotropin hormone is called luteinizing hormone. In women, LH triggers ovulation. In men, it stimulates the testicles to produce male hormones.

5. The Menstrual Cycle • An ovum is surrounded by other cells within a thin capsule of tissue to form a follicle. • At birth, each ovary has about 300,000 to 400,000 immature follicles, and the ovaries do not produce any new follicles during a woman’s lifetime. • The average length of an adult human menstrual cycle is about 28 days.

6. Preovulatory Phase (Day 5 to 13) • This phase is also referred to as the follicular or proliferative phase.

7. Ovulation (Day 14) • The LH surge signals the onset of ovulation within 12 to 24 hours. • At ovulation, the follicle ruptures and the ripe ovum is expelled into the abdominal cavity, where it will soon be picked up by a Fallopian tube.

8. Postovulatory Phase (Days 15 to 28) • If the egg is fertilized by a sperm, it continues its trip through the Fallopian tube and implants itself in the endometrium.

9. Menstruation (Days 1 to 14) • With the decline in levels of estrogen and progesterone, there is loss of the hormones that were responsible for the development and maintenance of the endometrium.

10. Length of the Menstrual Cycle • Most women have cycles that vary in length by 8 days or more.

11. Menstrual Synchrony and Pheromones • They were attracted by natural body scents called pheromones. Pheromones are defined as “a substance secreted by an animal to the outside of that individual which is then received by another individual…of the same species, which then elicits some behavioral or development response in the latter.”

12. Attitudes About Menstruation: Historical Perspectives • The biblical Hebrews regarded a menstruating woman as “unclean” or “impure,” and believed that she could transfer her condition of uncleanliness to a man during sexual intercourse.

13. Attitudes About Menstruation Today • Myths that women should avoid bathing, swimming, and exercise during menstruation are common. • Bathing, washing their hair and swimming are not the only things many women do without during menstruation. • The discharge consists of nothing more than some sloughed off endometrial tissue, mucus, and a small amount of blood.

14. Amenorrhea • Amenorrhea refers to the absence of menstruation for 6 months or longer. Oligomenorrhea is the absence of menstruation for shorter intervals, or unevenly spaced menstrual periods. • Girls with high body fat levels generally start menstruating at a younger age than girls with low levels of body fat.

15. Amenorrhea is common among female athletes. Women with the eating disorder anorexia nervosa are often considerable under weight, and as a result rarely menstruate. • While poor health can result in amenorrhea, amenorrhea can also affect a woman’s health. • For example, the low levels of estrogen usually associated with amenorrhea often result in long-term problems such as osteoporosis and cardiovascular disease. • Thus, a premenopausal woman who is not menstruating regularly should consult a physician.

16. Premenstrual Syndrome (PMS) • PMS refers to a group of physical and/or emotional changes that many women experience in the last 3 to 14 days before the start of their menstrual period. • Only about 75% of women with regular menstrual cycles have some symptoms.

17. To be diagnosed with PMDD, a woman’s symptoms must “markedly interfere” with social relations, work, or education, and include at least one of the following symptoms: markedly depressed mood, marked anxiety or tension, persistent and marked irritability or anger, or “marked affective lability” (extreme changes in mood, such as sudden sadness). • It is estimated that 3 to 8% of all women in their reproductive years have PMDD.

18. Dysmenorrhea • Symptoms can include backaches, headaches, a feeling of being bloated, and nausea.

19. Endometriosis • Endometriosis refers to a condition in which the endometrial tissue also grows outside the uterus.

20. Toxic Shock Syndrome (TSS) • TSS is caused by toxins produced by a bacterium.

21. Regulation of Male Hormones • In men, the hypothalamus, pituitary gland, and testicles operate in a feedback loop much like the feedback loop in women.

22. Hormones and Sexual Desire • Research on sex and hormones relies heavily on two types of studies: those investigating the effects of administering hormones and those investigating the effects of a loss of hormones. • After puberty in boys, 6 to 8 milligrams of testosterone are produced every day, and among very young adolescent boys, sexual activity increases as testosterone levels increase. • There is a decline in testosterone production as a man grows older, but men who are sexually active often have high testosterone levels.

23. Hypogonadal men show very little interest in sex. • In some parts of the world, men who were once used as harem attendants were forced to have their testicles removed so that they would not be interested in the women they were supposed to protect. • In many cases this worked, especially if the men were not yet sexually experienced at the time of castration. • However, there were also stories of some eunuchs having the time of their lives, like roosters guarding a hen house.

24. Modern studies of castrated men show, however, that sex drive and behavior are drastically or completely suppressed in a high percentage of cases. • In Europe and in the United States, some judges now offer male sex offenders a choice between prison and chemical castration with antiandrogen drug called DepoProvera. This drug and others like it severely reduce testosterone production, and often reduce interest in sex.

25. What about women? The loss of estrogen and progesterone at menopause does not reduce sexual desire in most women. In those postmenopausal women who do show a decrease, estrogen replacement therapy alone generally has no effect.