Frequently Asked Questions

Hormones are organic chemical messengers produced by endocrine glands located throughout the body. They coordinate physiology and behavior by regulating body functions and helping to control the body.

Hormones have specialized functions and can only act on certain cells, called target cells. Target cells have specific receptors for particular hormones. There must be a particular number of target cells available for a specific hormone to produce any effects. Hormones travel to virtually every part of the body through the bloodstream so can interact with any cell that is the appropriate receptor.

Yes! Of course all medical doctors have basic training in all bodily systems. Doctors who specialize particularly in understanding and treating disorders involving the hormone or endocrine system are called endocrinologists. The word endocrine comes from the Greek word endon, which means "within", and krinein, which means "to release". The Greek word hormon means, "to excite" or "to set in motion".

Hormones are produced by hormone glands. A hormone gland may produce more than one type of hormone. There are many hormones in the human body that each has a specific purpose and function. Some of the more common hormones are mentioned below:

Testosterone, estrogen, progesterone, thyroid are common hormone names. Thyroid Stimulating Hormone (TSH) causes the thyroid gland to produce and release thyroid hormones. Thyroid hormone controls the basal metabolic rate and plays an important role in growth and maturation. Thyroid hormones effect almost every organ in the body. Prolactin helps promote lactation, or breast milk production. This can occur in males and females. Oxytocin, produced by the pituitary, helps during birth by causing contractions and is also important in the suckling reflect of infants. Vasopressin is also known as an antidiuretic hormone (ADH). Alcohol inhibits production of ADH and thereby is the reason for the increased need for urination after drinking alcoholic beverages.

Others less commonly known to the general public are the gastrointestinal hormones that include gastrin, secretin, cholecystokinin. Growth hormones (GH) are naturally produced to help stimulate and regulate growth; however they do not directly induce growth of the skeleton. As with many hormones it acts as messenger to the liver, kidneys and other organs responsible for body growth. Adrenocorticotropic hormone, or ACTH triggers the adrenals to release the hormone cortisol, which regulates carbohydrate, fat, and protein metabolism and blood pressure. The adrenal glands sit above the kidneys and are also responsible for the body's fight or flight response. Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) control the production of sex hormones (estrogen and testosterone) and sperm and egg maturation and release. Melanocyte-Stimulating Hormone (MSH) regulates the production of melanin, a dark pigment, by melanocytes in the skin. Increased melanin production produces pigmentation or tanning of the skin; in certain conditions excessive production of melanocyte-stimulating hormone can cause darkening of the skin.

Synthetic hormones are those produced outside the body in a laboratory.

In the brain the endocrine glands include the Pineal gland, the Hypothalamus, and the Pituitary. The Thyroid and Parathyroid glands are located in the neck area. The Adrenal glands are located just above the kidneys. The Pancreas is near the gut area. The Ovaries (in females) and Testes (in males), gonads, are in the reproductive region of the body. There are also endocrine tissues of the gastrointestinal tract that are organized in small clumps of endocrine cells and scattered throughout the gut rather than being concentrated into a specific glandular organ.

It was once thought that each individual hormone was separate from the other. In more modern times science now knows that hormones are connected. This is much as members of a family have a connection to one another. We are each individuals within our families. But, for example, if a child excels in school by getting good grades the parents feel proud. If a member of a family gets arrested for using illegal substances their family members usually feel a sense of shame, even if they had nothing personally to do with the crime. Within the hormonal, or endocrine system, the major “players” are the Hypothalmus, the Pituitary, and the Adrenal glands. This is called the H-P-A axis because these glands are like the parents of the family.

Absolutely! Again, the body is similar to a family where there is the parent system, the sibling system, and the extended, or larger, family system. Of course families interact with work systems, community and social systems etc. but a family is still very much defined and easily identifiable. Family members can be identified by their last names, how similar they may look to one another, and of course their genetic makeup is more similar than non-family members. The endocrine system interacts with the nervous system, the immune system, the emotional system and more.

Hormones are released from the endocrine glands into the bloodstream where they are then carried to their targeted organs.

Many different parts of the brain are linked together to produce a whole constellation of feelings and perceptions. Neurotransmitter and hormones together help transmit messages that can result in what is felt as an emotion. Illness or dysfunction in any part of the endocrine system can affect the body’s ability to balance emotional highs or lows.

Many people wonder if “stress” is real or “just in your head”. The best way to answer this is to describe what happens in the body when a stressful event happens. As soon as an event is perceived as a threat, the hormones in the hypothalamus, pituitary, and adrenal glands (H-P-A) trigger the adrenal glands begin to release (within 1-3 minutes) epinephrine (adrenaline). At nearly the same time the sympathetic nerves release norepinephrine (adrenaline-like substance) throughout the body, but particularly to the heart, gut, and skin. The heart then begins to beat faster, the stomach feels nauseous, and the skin becomes filled with sweat. These, and other, are all important responses to prepare the body to defend itself in case of a threat (stressor).

Yes! The body is built to defend against brief, short-term or short-lived stress events. These occur as part of normal living. The endocrine system responds immediately to help us survive immediate threats (some of these, however, are perceived and may not be actual threats). The immune system (acts like an army to protect our bodies from outside attackers like germs, viruses etc.) takes longer to respond and may take hours or days to respond and mobilize to protect. However, when stress becomes chronic the immune system becomes impaired and may become overloaded much as an electronic wiring circuit in a house. When this happens a circuit may “blow out” or illness occurs. Chronic stress can shut down reproductive systems in both men and women, can stop a woman’s menstrual cycle, decrease sexual desire and much more.

The term “depression” is used in Western culture to mean many things. The terms, “major depression”, or “bipolar depression”, are clinical terms used by mental health professionals to describe very specific symptom clusters. There are many types of depression that can be serious and life-threatening and should be diagnosed and treated professionally. Hormones, of course, have been shown to affect mood and behavior. For example, thyroid hormone levels have been shown to be associated with some depressive symptoms. Excessive cortisol levels, especially in Cushing’s disease, have been strongly correlated with depressive symptoms. Growth hormone excesses have also been related to depression. It still remains unclear, however, whether depression causes a change in hormone production or whether imbalances in hormone levels cause depression. Is it first a chicken or egg? Either way both must be recognized and treated.

Sexual behavior is necessary for production of new life. The gonads (ovaries and testes) have two functions that include production of sperm or ova, and production of the steroid (primarily) hormones required for development of secondary sex characteristics that make humans male or female. Hormones affect sexual behavior not by acting as a “switch” to activate sexual behavior, but more to increase the probability that it will occur. After puberty the motivation to seek sexual contact increases due to production of sex hormones.

There are many factors that can influence hormone levels in the body. Stress, physical illness, monthly and daily circadian cycles, age and more can naturally influence levels of hormones in the body. Men in their sixties, for example, typically show decreases of circulating androgens in their flood, but approximately fifty percent of healthy men over the age of eighty have testosterone concentrations within the normal range for men ages 25 to 59. Why there are such variations is still unknown.

Research into why humans eat, over or under-eat is ongoing and still not understood completely. It appears that hormones do affect feeing behavior primarily by having an effect on sensory systems that are related to feeding. Hormones are known to be involved in the biology of why we desire to eat and the control mechanism of how much we eat. The hypothalamus (part of the H-P-A axis) is involved, but also other areas of the brain, including the posterior, or caudal, areas have the ability to act independent of the hypothalamus. The regulation of feeding in humans involves the endocrine and the nervous systems as well. Feeding is an incredibly complex process that involves both internal or intrinsic input messages (like the amount of fat stored in the body, levels of glycogen in the liver, the qualities of the food being digested, endocrine signals from the gut etc.) and external or extrinsic messages (such as food availability, psychological, cultural and media messages about food and body image etc.). Hormones do help signal a “stop eating” behavior, but of course this can be overwritten when such natural body messages are not listened to or observed. Food intake is, for example, higher during the luteal phase (high progesterone phase) of the menstrual cycle, is attributed to fluctuations in blood levels of sex steroid hormones.