Thyroid, Adrenal, Pituitary, oh my!
Posted on: November 11, 2005 | Posted in: Medical Information
The anterior pituitary secretes growth hormone, prolactin, follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, endorphins and other hormones. It does this in response to a variety of chemical signals from the hypothalamus…. –Wikipedia
The pea-sized pituitary gland seems to control just about everything, including the thyroid and its freqent partner in mysterious maladies: the adrenal gland. From what I’ve read, a frequent reason for thyroid medication not effecting the miraculous turnaround seen in some patients is the presence of an underlying adrenal insufficiency, so it may be useful to have a little overview of both. And that all starts with the pituitary gland.
Well, really it all starts with the hypothalamus, which tells the pituitary what to do… but it’s the teeny little pituitary that releases the aforementioned cornucopia of hormones that tell everything else what to do. Ovulation, fight or flight adrenaline rushes, metabolism regulating thyroid output, growth, etc., etc. The pituitary is kind of like the switchboard of the endocrine system, delivering the messages everything else needs. In our particular case, it’s TSH (thyroid stimulating hormone) and ACTH (adrenocorticotropic hormone) we’re concerned with.
TSH heads off to the thyroid, located on the front of your throat below your Adam’s apple, to regulate production of triiodothyronine (T3) and thyroxine (T4)—the T4 is later mostly converted to T3 by the liver. (The thyroid also produces calcitonin, which has a small part to play in calcium metabolism.) There’s a nice little feedback loop going that tells the hypothalamus what’s going on with your T3 & T4 levels, as well as other environmental factors, which in turn then affects the pituitary’s TSH production levels.
T3 and T4, in short, control the metabolism. If your metabolism is ’slow’ due to low T4 levels, you gain weight, and have trouble losing it. You’re feel sluggish and tired, even when you get “enough” sleep. Your hands and feet get cold too easily… you may just feel cold all the time. Your hair and fingernails grow slowly, and break easily. Your skin gets dry. Your sex drive diminishes. It truly does affect everything.
Meanwhile ACTH is shuttled off to the adrenal glands, located on top of your kidneys, to help regulate production of various adrenal hormones like cortisol, epinephrine and norepinephrine, as well as secondary production of testosterone and other things. But primarily, cortisol is what we’re concerned with here.
Cortisol affects the metabolism also, in several ways related to stress and survival situations. It stimulates release of amino acids and the breakdown of fat, the subsequent conversion of glucose from the newly released aminos and lipids, and the regulation of glucose reuptake by the body… all to give the body enhanced energy in stressful situations.
Chronically high cortisol levels not only cause their own health problems (such as high blood pressure and disproportionate accumulation of abdominal fat, both of which in turn cause their own set of health problems), but chronic overstimulation of the adrenal glands can cause adrenal exhaustion, paradoxically leading to underproduction of adrenal hormones.
Lack of these hormones can mess up all sorts of things, of course. The adrenal gland helps regulate electrolyte levels, and therefore fluid retention and/or release (which, IMO, is intriguing, given my previous major problem with water retention). Actually, there is a whole list of symptoms of adrenal insufficiency, including fatigue, low blood pressure, muscle weakness, depression, irritability, appetite loss, and hypoglycemia.
Yet to be uncovered in my ongoing studies: Why the thyroid and adrenal gland would often malfunction in tandem. Is it a chronic stress thing? An inherited issue? Does the malfunction of one ‘wear down’ the other? Stay tuned…
technorati tags: hypothyroidism, hypothyroid, thyroid, endocrine, health, medical, mivox