Teenagers are often described as raging balls of hormones. But the truth is that hormones affect us in every stage of life, from development in the womb to the hot flashes of menopause.
The body produces the chemicals we call hormones to control all kinds of body functions. Glands, the organs that secrete hormones, make up the endocrine system, which helps to regulate functions such as growth, metabolism, and reproduction. Imagine hormones as the Pony Express of the body, delivering important chemical messages and instructions.
The brain produces seven of the more than 50 hormones in the body. Each has a different, crucial role. “No one hormone is more important than another,” says Dr. N. Scott Litofsky, chief of the Division of Neurological Surgery at the University of Missouri. Like any well-oiled machine, each component must do its job correctly to guarantee success.
At the center of it all is the pituitary gland. This is probably the most famous gland in the human body, and is referred to as the “master gland” because it controls the function of most of the other glands in the endocrine system. This pea-sized organ resides in the hypothalamus region of the brain and is most closely associated with the crazy changes we all go through in our teenage years.
During adolescence, the brain signals the pituitary gland to secrete hormones that bring on puberty. Luteinizing and follicle-stimulating hormones, also known as LH and FSH, play an important role in reproduction. The pituitary gland sends these hormones to stimulate the ovaries in women and the testes in men. As a result, the body begins to grow and we have to endure all the awkwardness of puberty, from voice change to body hair to, gulp, boobs!
Hormones and reproduction go together like the sperm and the egg — a perfect match. It takes hormones to get our reproductive organs to develop and work properly, to arouse us enough to use those organs, and to maintain the end result of those processes — a baby.
Two more hormones produced by the pituitary gland are essential for reproduction. When a woman is pregnant, the hormone oxytocin stimulates contractions in the uterus during labor. After the baby is born, the pituitary gland produces prolactin. This hormone spurs milk production while at the same time suppressing FSH and LH, which are necessary for menstruation. The elevated prolactin in the system prevents pregnancy. “It makes sense from an evolutionary standpoint,” Litofsky says. A woman does not have the physical resources to care for an infant during pregnancy.
Of course, before reproduction, there must first be physical attraction, which hormones also play a role in. Researchers at Florida State University published a study in Psychological Science that suggests the scent of a woman can increase hormone levels in men. Men who sniffed the T-shirt of an ovulating woman had a higher level of testosterone than men who sniffed a T-shirt of a woman who was at a different point in her cycle. This indicates men are more sexually receptive to a woman during her fertile period, even if they’re not aware why.
As we edge into our golden years and put childbearing behind us, hormones are most closely associated with the dreaded onset of menopause in women. Also known as “the change,” menopause occurs mostly in women over 40 and technically refers to the time beginning 12 months after the last period. Ovaries have stopped producing eggs and estrogen. Symptoms caused by a change in hormones include hot flashes, low sex drive and sleeping problems.
But hormones have an impact on more than just reproduction and sex drive. Experiencing stress can also affect hormones. When the brain feels threatened — for instance, losing control while driving fast on the highway or being confronted by a stranger — it sets off a warning throughout the body, including the brain, that causes the pituitary gland to release the hormone ACTH, or adrenocorticotropic hormone, which then stimulates the adrenal gland to produce adrenaline and cortisol.
Adrenaline, also known as epinephrine, increases energy and raises blood pressure and heart rate. The extra boost allows muscles to exert more strength. Cortisol increases the stream of oxygen and glucose to the brain and muscles, giving a person heightened sensibilities, and suppresses nonessential processes such as digestion.
In some extreme cases, it has been reported that adrenaline has given people superhuman strength. In 2006, a mom in Quebec fought off a polar bear to save her son and his friends when the bear approached the children during a street hockey game. She suffered only a few minor scratches and a black eye before a neighbor shot the bear.
Another important hormone produced in the brain by the pituitary gland is antidiuretic hormone, also known as ADH. It controls the body’s water metabolism. As Litofsky explains, if a person loses a lot of blood, the brain realizes that and sends ADH as a signal to the kidney to hold onto fluid. Or if a person becomes dehydrated, the brain detects too much salt in the blood and tells the pituitary gland to send ADH.
The pituitary gland also produces human growth hormone, which is sent to the liver to stimulate the production of insulin-like growth factor. This travels to the tissue and aids in growth. Human growth hormone has been abused by athletes and some doctors try to sell it as a “fountain of youth” tonic, capable of fixing a long list of ailments. The pituitary also produces thyroid-stimulating hormone, which stimulates the thyroid to produce the hormones that are responsible for our metabolism in general.
Steroids, like human growth hormone, are also misused by athletes. Just ask any major league baseball player. To enhance performance, athletes can use testosterone, a hormone produced by the testes in men and the ovaries in women. Steroids help an athlete build muscle more quickly and might help quicken recovery from tough workouts. But the quick fix comes at a high price. Steroid use can cause a host of negative repercussions including depression, aggression, and tumors.
While both men and women have the same hormones, they produce them in different quantities, and some don’t have much to do with body function. From menstruation to menopause, it seems like when it comes to hormones, women have more to worry about. “They have more cyclical patterns that require regulation than men do,” Litofsky says. But, the reason for worry might not be all scientific. “It may be that men don’t talk about their hormone-related issues.”
The bottom line is that the human body is complex, and hormones relay important information from the brain to keep it working. “We’re not static beings, and things change from moment to moment,” Litofsky says. “The body needs to adapt to those changes, and that’s how hormones help us.”
This article was first published in Brain World Magazine’s Spring 2010 issue.
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