The Role of the Hypothalamus and Pituitary Gland In Thyroid Health
Published March 30 2015
When someone has a hormone imbalance, most medical doctors focus on the gland which is responsible for the secretion of the hormone. And in many cases a hormone deficiency will result in hormone replacement. For example, most people with hypothyroidism will be told to take thyroid hormone medication, while many people with a deficiency of progesterone or testosterone will be told to take bioidentical progesterone or testosterone. While hormone replacement is sometimes necessary, often times very little attention is paid to the hypothalamus and pituitary gland, which play key roles in the secretion of these hormones.
Most thyroid conditions are autoimmune, which is why I focus a great deal on trying to detect and remove the autoimmune trigger. However, problems with the hypothalamus and pituitary gland can be a factor in one’s thyroid or autoimmune thyroid condition, as I’ll discuss later in this article. But what I’d like to first do is to briefly talk about the hypothalamic-pituitary-thyroid axis, the hypothalamic-pituitary-adrenal axis, and the hypothalamic-pituitary-gonadal axis.
Hypothalamic-pituitary-thyroid axis. With regards to thyroid health the hypothalamus secretes a hormone called thyrotropin-releasing hormone (TRH), which in turn stimulates the pituitary to release thyroid stimulating hormone (TSH), and this hormone stimulates the thyroid gland to secrete the hormones thyroxine (T4) and tri-iodothyronine (T3). Mostly T4 is produced, and the conversion of T4 to T3 takes place in the liver and gut.
Hypothalamic-pituitary-adrenal axis. With regards to adrenal health the hypothalamus secretes hormones called corticotropin-releasing hormone (CRH) and vasopressin, which in turn stimulates the pituitary to release adrenocorticotropic hormone (ACTH), and this hormone acts on the adrenal cortex to produce glucocorticoids. Cortisol is the main hormone produced by the adrenal cortex. Just as is the case with thyroid hormone, through negative feedback cortisol will inhibit the hypothalamus and pituitary gland, which in turn will decrease the secretion of CRH and vasopressin, and ultimately cortisol. Epinephrine and norepinephrine are produced by the adrenal medulla.
Hypothalamic-pituitary-gonadal axis. In this axis, gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus, which in turn causes the pituitary gland to produce luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and these travel through the blood stream and in turn cause the gonads to produce estrogen and testosterone. Of course in females FSH and LH primarily cause the ovaries to produce estrogen, whereas in men LH causes the testes to produce testosterone, while FSH plays a role in the formation of sperm. Of course females produce some testosterone, and males produce a small amount of estrogen.
Focusing On The Hypothalamus and Pituitary Gland
When someone is dealing with an imbalance of one or more of the hormones mentioned (thyroid hormone, cortisol, progesterone, etc.), the focus is usually on replacing the hormone and/or directly supporting the gland. So for example, if someone has a hypothyroid condition, the conventional medical approach is to have the person take thyroid hormone medication. On the other hand, many natural healthcare professionals might give nutritional support such as tyrosine, iodine, selenium, and perhaps a thyroid glandular. And of course some healthcare professionals do both. Although some people do need to take thyroid hormone medication, and while giving nutritional support to the thyroid can be beneficial at times, it doesn’t address the hypothalamic-pituitary-thyroid axis.
It’s a similar situation with the adrenals, as if someone has depressed cortisol levels, one doctor might want to provide bioidentical cortisol, while another doctor will recommend nutrients and herbs such as licorice, vitamin C, pantothenic acid, an adrenal glandular, etc. I’m not criticizing either approach, although I would try to avoid bioidentical cortisol whenever possible. I do frequently give herbs and nutrients to support the adrenals. However, most adrenal problems involve an imbalance of the hypothalamic-pituitary-adrenal axis. Giving bioidentical cortisol of course won’t do anything for the HPA axis, but the same is true for herbs and nutrients which directly support the adrenal gland.
What Factors Affect The Hypothalamus and Pituitary Gland?
In order to improve the communication between the hypothalamus and pituitary gland, it’s important to understand some of the common factors which can cause dysregulation in the first place.
1) Chronic stress. This is probably the biggest factor which causes HP-Axis dysregulation. Obviously the adrenals are greatly affected with regards to stress, but chronic stress affects both the HPA-axis and the HPT-axis (1) (2). And the activation of the HPA-axis will also inhibit the HPG-axis (3) (4).
2) Inflammation. In past articles and blog posts I’ve spoken about cytokines, which regulate inflammation. Cytokines also play a role in the communication between the hypothalamus and the pituitary gland, as they normally stimulate the HPA axis and suppress the HPT axis and HPG axis (5) (6) (7). However, thyroid autoimmunity usually involves an increase in pro-inflammatory cytokines, which in turn can cause miscommunication between the hypothalamus and pituitary gland (8) (9), and this in turn can affect the adrenals, thyroid, and/or gonads.
3) Neurotransmitter imbalances. Some of the neurotransmitters can modulate the HP-Axis. Numerous studies show that serotonin activates the HPA axis (10) (11). Dysregulation of the HPA axis seems to be a factor in depression (12), which usually involves low serotonin levels. It also appears that dopamine plays a role in modulating the HPA axis (13) (14).
4) Medications. Certain medications can cause problems as well. For example, there is evidence that inhaled corticosteroids, such as those used in asthma, can result in HPA axis suppression, and thus lead to adrenal insufficiency (15) (16). Corticosteroids can also inhibit the HPT axis, and thus lead to hypothyroidism (17) (18). Statins are another drug which can potentially affect the hypothalamus and pituitary gland, as I came across a study which showed that statins can potentially lower testosterone levels by affecting the HPG axis (19).
How To Correct HP-Axis Dysregulation
If someone has HP-Axis dysregulation they will want to do the following:
1) Address those factors I just mentioned which can be causing HP-axis dysregulation. This is obvious, as while it’s important to give some support to the hypothalamus and pituitary gland, it of course is necessary to remove those factors which caused the dysregulation in the first place. In autoimmune thyroid conditions the two biggest culprits which cause HP axis dysregulation are stress and inflammation. This is why I frequently discuss these factors, as if someone doesn’t do a good job of handing the stress in their life then it will be difficult, if not impossible to fully recover. Similarly, Graves’ Disease and Hashimoto’s Thyroiditis involve inflammation which also needs to be addressed.
With regards to stress management, most people know what to do, but simply don’t block out the time to do it. I’m not going to discuss this here, as I’ve written other articles and blog posts on this topic. One of these you might want to check out is entitled “Blocking Out Time To Manage Your Stress Is Essential“. Another one worth reading is “Chronic Stress and Thyroid Autoimmunity“.
I probably don’t need to talk much about eating well here, but since it’s so important I’ll briefly mention it. Just about everyone reading this knows that they should eat a diet consisting of whole foods, while avoiding the refined foods and sugars, fast food, etc. Eating poorly will obviously have a negative effect on your overall health, and so if someone has any type of health issue it is important to eat well. And this includes HP-axis dyregulation.
2) Get sufficient sleep each night. Earlier I forgot to mention sleep as being a factor which can affect the hypothalamus and pituitary gland. There are numerous studies which show that sleep deprivation can affect both the HPA axis and the HPT axis (20) (21) (22). One of these studies showed how in those people with sleep disorders, altered hypothalamopituitary-adrenal and hypothalamopituitary-thyroid axis activity is associated with impaired glucose regulation (22). And so even if someone is eating well, if they have poor sleep this can result in blood sugar imbalances. Obviously some people who have problems falling and/or staying asleep make a sincere effort each night to get a good night’s sleep, but are unable to. In these people it of course is necessary to try addressing those factors which are causing the sleep issues, which many times can be challenging. But there are also a lot of people who intentionally neglect their sleep, as they get five to six hours of sleep on a regular basis when they want to attempt to get at least seven or eight hours each night.
3) Consider taking herbs and/or glandulars to support the HP-axis. There are a few different ways to support the HP-axis. Adaptogenic herbs such as rhodiola, ashwagandha, eleuthero, and maca many times can help a great deal. Herbs such as rhodiola, ashwagandha, and eleuthero seem to have a greater impact on the HPA axis (23) (24) (25), and thus these are the main herbs which should be considered to help deal with chronic stress. On the other hand, maca seems to have a greater impact on the HPG axis (26), and thus might be considered more for imbalances in estrogen and progesterone. There are a few studies which show that ashwagandha can help to support the HPT axis (27) (28) (29).
Another option is to take glandulars which support the hypothalamus and pituitary gland. And although there are times when I use glandulars in my patients to support the pituitary gland and hypothalamus, there isn’t any scientific evidence I’m aware of which shows that these glandulars provide any benefits. This might sound discouraging to some people reading this, although keep in mind that this doesn’t mean these glandulars can’t be beneficial, as there also aren’t any studies which show that they aren’t effective. In other words, the lack of clinical trials conducted on these glandulars, as well as on other supplements and herbs, doesn’t mean that they can’t benefit some people. There are far more studies conducted on drugs, and the reason for this is not because drugs are more effective than natural treatment methods, but instead the pharmaceutical companies have plenty of money to spend on these studies, and the same isn’t true when it comes to studies on herbs and other supplements.
So hopefully you have a better understanding as to the role that the hypothalamus and pituitary gland play in thyroid health. The hypothalamus communicates with the pituitary gland, which in turn releases hormones that signals the thyroid gland to release thyroid hormone, the adrenals to release cortisol, and the gonads to secrete the sex hormones. As a result, if someone has dysregulation of one of these axes it can affect the secretion of these hormones. Some of the main factors which can affect the hypothalamus and pituitary gland include chronic stress, inflammation, neurotransmitter imbalances, and certain medications. These factors obviously need to be addressed in order to correct HP-Axis dysregulation, and giving support in the form of adaptogenic herbs and/or glandulars for the hypothalamus and pituitary gland should be considered in some cases.