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Have you ever suffered from missed or painful periods, out of control food cravings, temperature dysregulation, weight loss, weight gain, debilitating cramping etc etc etc. I can almost guarantee that 9 out of 10 women that read this article can agree that at some point in your life you felt like your hormones were out of balance. I think we can all agree that being a woman and feeling in control of your body can be a lot of work. If you suffer from any symptoms that something isn’t right whether you are young and think “I’m not in menopause, it’s probably just stress” or you are older and wonder “well, I guess i'm going into menopause, and this is just how it is” then it is probably time you dig in, investigate and see where your hormones are. Having your menstrual cycle isn’t supposed to be painful and excruciating. Back in the day before all the environmental toxins and endocrine disruptors, women’s periods just appeared with minimal signs or symptoms. I know you are probably thinking, “That’s not possible!” There are many reasons that your hormones can be off balance. Endocrine dysfunction, stress, excessive alcohol consumption, PCOS, perimenopause, menopause and much more.
In this article we are going to look at the basics of each of our glands that produces one or more hormones that affect our health and show us what an amazing specimen the female body is.
The Hypothalamus
This gland is located in the brain and controls the release of hormones from the pituitary gland. It helps to keep our body in a stable condition (homeostasis). The hypothalamus responds to a variety of signals from the internal and external environment including body temperature, hunger, fullness, blood pressure and levels of hormones in the circulation. It also responds to stress and controls our daily bodily rhythms such as the night-time secretion of melatonin from the pineal gland, diurnal changes in cortisol (the stress hormone) and body temperature over a 24-hour period which will be discussed in a future article. The hypothalamus collects and combines all this information and puts changes in place to correct any imbalances.
One set of cells sends anti-diuretic hormone and oxytocin down to the pituitary gland where these hormones are released directly into the bloodstream. Anti-diuretic hormone regulates the amount of fluid in the body and causes water reabsorption at the kidneys thus preventing dehydration. Oxytocin stimulates contraction of the uterus in childbirth and is important in breastfeeding.
The other set of cells produce hormones that control the gonads, thyroid gland and adrenal cortex.
The Pituitary gland
The pituitary gland is referred to as the 'master gland' as the hormones it produces controls so many different processes in the body. It secretes a variety of hormones into the bloodstream which act as messengers to transmit information from the pituitary gland to distant cells regulating their activity. For example, the pituitary gland produces prolactin, which acts on the mammary glands in the breasts to induce milk production. The pituitary gland also secretes hormones that act on the adrenal glands, thyroid gland, ovaries and testes, which in turn produce other hormones. Through secretion of its hormones, the pituitary gland controls metabolism, growth, sexual maturation, reproduction, blood pressure and many other vital physical functions and processes.
Regulated by the hypothalamus and the circulatory hormone level, the pituitary gland produces the following hormones and releases them into the bloodstream:
Adrenocorticotropic hormone (ACTH): stimulates the adrenal glands to secrete steroid hormones, mainly cortisol
Growth hormone: regulates growth, metabolism and body composition via acting on the liver, bones, adipose tissue (fat deposit) and muscle
Luteinizing hormone (LH) and follicle stimulating hormone (FSH): known as gonadotrophins. They act on the ovaries or testes to stimulate sex hormone production and egg or sperm maturity
Prolactin: stimulates milk production in the mammary glands
Thyroid stimulating hormone (TSH), which stimulates the thyroid gland to secrete thyroid hormones.
Two hormones are produced by the hypothalamus and then stored in the pituitary gland before being secreted into the bloodstream. These are:
Anti-diuretic hormone: controls water balance and blood pressure
Oxytocin: stimulates uterine contractions during labor and milk secretion during breastfeeding.
The Adrenal Glands
There is one adrenal gland above each of the kidneys. Each gland is composed of the adrenal cortex and the adrenal medulla. The glands secrete different hormones which act as 'chemical messengers'.
The adrenal cortex produces five hormones:
Mineralocorticoids: Aldosterone. This hormone helps to maintain the body’s salt and water balance, which is important for maintaining blood pressure.
Glucocorticoids: predominantly cortisol. This hormone helps to regulate body metabolism. Cortisol is also released during the ‘stress response’ to illness. Cortisol stimulates glucose production to help maintain blood glucose levels. Keep a look out on stress management articles to dive deeper into cortisol.
Adrenal androgens: the male sex hormones, mainly dehydroepiandrosterone (DHEA) and testosterone. These are present both in men and women and play a role in early development of the male sex organs in childhood and are important for the normal onset of female body hair following puberty. These can be abnormal in women with PCOS.
Progesterone and estrogen: the female sex hormones produced in small amounts in comparison to the ovaries and continue to produce after menapause when the ovaries are no longer producing.
The adrenal medulla produces catecholamines:
Catecholamines include adrenaline, noradrenaline and small amounts of dopamine – these hormones are responsible for all the physiological characteristics of the stress response, the so called 'fight or flight' response, which can include increased heart rate, blood pressure, breathing rate, dilated pupils in the eye, and looking flushed or pale. Keep a look out on stress management articles to dive deeper into these hormones.
The Thyroid Gland
The thyroid gland produces hormones that regulate the body's metabolic rate, growth and development. It plays a role in controlling heart, muscle and digestive function, brain development and bone maintenance. Its optimal function depends on a good supply of iodine from the diet. Cells producing thyroid hormones are very speci
alized in extracting and absorbing iodine from the blood and incorporating it into the thyroid hormones.
The pituitary gland produces and sends out a hormone called thyroid-stimulating hormone (TSH). TSH then tells the thyroid gland how much hormone to produce and secrete. TSH levels in your blood are rising and falling depending on your body’s needs, to produce more or less thyroid hormones.
The thyroid gland produces thyroxine (T4), which is a relatively inactive prohormone, and the highly active hormone called triiodothyronine (T3). The thyroid gland produces about 20% of the active T3 but mainly produces the inactive prohormone T4. Once secreted by the thyroid, specific enzymes in other tissues like the liver or kidneys convert T4 into the active hormone T3.
The thyroid gland also produces C-cells that produce calcitonin. Calcitonin plays a role in regulating calcium and phosphate levels in the blood, which is important for your maintain healthy bones.
The Ovaries
The ovaries are a key part of the female reproductive system. Each woman has two ovaries, one on each side of teh uterus. The ovaries have two main reproductive functions in the body. They produce oocytes (eggs) for fertilization and they produce the reproductive hormones, estrogen, progesterone and androgens.
The function of the ovaries is controlled by gonadotrophin-releasing hormone (GnRH) released from the hypothalamus which in turn stimulates the pituitary gland to produce luteinizing (LH) and follicle stimulating hormone (FSH). These hormones are carried in the bloodstream to the ovary to regulate the menstrual cycle.
The Menstrual Cycle
The ovaries release an egg at the midway point of each menstrual cycle. Usually, only one egg from one ovary is released during each menstrual cycle, known as ovulation. A female baby is born with all the eggs that she will ever have. This is estimated to be around two million, but by the time a girl reaches puberty, this number has decreased to about 400,000. From puberty to the menopause, only about 300 - 400 eggs will be released through ovulation.
The ovarian typically phases through a 28-day menstrual cycle. Ovulation occurs mid-cycle.
In the ovary, all eggs are initially enclosed in a single layer of cells known as a follicle, which supports the egg. During the follicular phase (first part of the menstrual cycle), one or two ovarian follicles grow due to the action of FSH. As the follicle grows it produces estradiol. As estradiol levels rise this induces the hypothalamus and pituitary gland to make high levels of LH (and some FSH) at the midpoint of the cycle to induce ovulation. During ovulation, the egg is released from the follicle in the ovary into the fallopian tube. Once the egg has been released at ovulation, the empty follicle that remains becomes the corpus luteum (CL). The CL produces the hormones progesterone (in a higher amount) and estrogen (in a smaller amount). These hormones prepare the lining of the uterus for a potential pregnancy (in the event that the released egg is fertilized by sperm in the female reproductive tract). If the released egg is not fertilized and pregnancy does not occur during a menstrual cycle, the corpus luteum breaks down and the secretion of estrogen and progesterone stops. Due to the fall in levels of progesterone, the lining of the womb starts to fall away and is lost from the body through menstruation, or a ‘period’. Menstruation usually lasts around 3 – 5 days. Day 1 of menstruation signals the start of a new menstrual cycle.
Menopause refers to the ending of a woman's reproductive years following her last menstruation and is around 51 years of age. This is caused by loss of the remaining follicles in the ovary. When there are no more follicles (which each contain an egg), the ovary no longer makes the hormones estrogen and progesterone, which regulate the menstrual cycle. As a result, the occurrence of menstrual cycles and monthly periods cease.
Hope this helps understand the intricate work our hormones play in our body for our reproductive and metabolic health. Stay tuned for more articles on hormones focusing on those related to stress response, sleep, and improving mood and another article looking more into some of the dysfunctions of our hormones and how that can affect our health and metabolism. If you're frustrated with you weight, worried about your metabolic health and need help getting start, give us call at 480.266.4122 or schedule an appointment.