Resistance to Thyrotropin
Have you ever wondered about all the millions of functions your internal system has and how it might make you feel or even act at times? 1 This is all due to the Endocrine system, which is a network of glands that secrete chemicals called hormones to help your body function properly. Hormones are chemical signals that coordinate a range of bodily functions. The endocrine system works to regulate certain internal processes. One of the main keys as to how you react or not react has to do with your hormones and all the chemical reactions that go along with them. 2 A hormone is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior. 3 Hormones have diverse chemical structures, mainly of 3 classes: 4 eicosanoids, steroids, and amino acid derivatives (amines, peptides, and proteins). The human body consists of several major hormones in survival essentials and also in what you mainly distinguish hormones to be such as sexual or mood behavior, but the major endocrine glands include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus, gastrointestinal tract and adrenal glands. Now we can ask , what would happen if our Endocrine system wasn’t working properly? What if our hormones were secreting too little or too much and throw off out internal homeostasis. In this case we will be focusing on the effects of a thyroid disorder and why this might happen to an individual.
Genetic factors play the most important role, in my opinion, within the etiology of many thyroid diseases. Almost all types of genetic disturbance have been reported to be operative in thyroid disorders, including single gene defects know as autosomal, x-linked, dominant and recessive modes of inheritance. One main element to thyroid disorders we will go over will be the resistance to thyrotropin-releasing hormone (TRH) syndrome, which is a type of central congenital hypothyroidism characterized by low levels of thyroid hormones due to insufficient release of thyroid-stimulating hormone (TSH) caused by pituitary resistance to TRH. There are two forms of resistance to thyroid hormones known as Generalized Resistance to thyroid Hormones (GRTH) which is 75% of the reported cases as familial, mutation in the thyroid hormone receptor, and Selective pituitary resistance to thyroid hormones (PRTH) which are results of mutations in the thyroid hormone receptor. 5 All types of hyperthyroidism are due to an overproduction of thyroid hormones, but the condition can occur in several ways; 6 Grave’s disease, the production of too much thyroid hormone .Toxic adenomas, where the nodules develop in the thyroid gland and begin to secrete thyroid hormones, upsetting the body’s chemical balance; some goiters may contain several of these nodules. 5 Subacute thyroiditis , an inflammation of the thyroid that causes the gland to “leak” 7 excess hormones, resulting in temporary hyperthyroidism that generally lasts a few weeks but may persist for months .Pituitary gland malfunctions or cancerous growths in the thyroid gland: 6 Although rare, hyperthyroidism can also develop from these causes. These are typically given from one or both parents to the offspring and cause the disorder, but are usually treatable.
Hormones are controlled and released from several glands in the body and the system we know it as the Endocrine system ” the master” gland is called the Hypothalamus located in the brain. Hormones get secreted into the circulatory system, which compared to the nervous system , the reactions happen a lot slower, but have a much longer retention to the effect. 8 The thyroid is a butterfly-shaped gland within your neck, just above your collarbone. 9 It is one of your endocrine glands, which make hormones. 10 Thyroid hormones control the rate of many activities in your body, and include how fast you burn calories and how fast your heart beats and many more of these activities are your body’s metabolism. 11 In most cases thyroid problems include , Goiter , an enlargement of the thyroid gland, hyperthyroidism , which is when your thyroid gland makes more thyroid hormones than your body, or hypothyroidism in which your thyroid gland does not make enough thyroid hormones. Now we can go over the main hormones , their locations and it’s function in more detail. The pituitary gland is composed of an anterior and posterior portion in which to they each have a distinguished job. The posterior pituitary gland is major in Oxytocin, which stimulates uterine contraction during child birth and breast contraction for milk release. Anti-diuretic Homone (ADH), also known as vasopressin, stimulates re-absorption of water from kidney tubules ,hypo causes diabetes insipidus, large amounts of urine produce. In the anterior , we have the Human Growth Hormone (HGH) , Growth, when there’s too little of it causes dwarfism , and when it produces too much , gigantism. In the pineal gland, one of the main one’s is melatonin, a hormone produced by the pineal gland in darkness but not in bright light , melatonin receptors in the brain react to this hormone and synchronize the body to the 24 hour day/night rhythm, informing the brain when it is day and when it is night. Melatonin is derived from serotonin, helping sleep an wake cycles. In the adrenal glad , we have the adrenal medulla containing adrenaline which prepares the body from “fight or flight” and has many effects such as heart rate increase, increase in respiratory rate, metabolic increase, force of muscle contraction improves, muscular fatigue delayed, and blood supply to the bladder and the intestine reduced, their muscular walls relax. T3, short for the term for Triiodothyronine which is the name given to this form of thyroid hormone. is probably the single most important thyroid hormone, because it is the most biologically active thyroid hormone and most of it’s functions we associate with your thyroid gland that come from the interactions of T3 in your cells. But how does your body create T3? Triiodothyronine is created from the most abundant thyroid hormone in your body Thyroxine also known as T4. Enzymes remove an iodine at a certain place on the T4 hormone and turns it into the most active thyroid hormone we need T3, the bodies does this because we do not require T4 as much as we need T3. So, if you are currently under a lot of stress, or needing to produce more energy or heat, then your body can rev up the thyroid conversion process to produce more T3. Now on the opposite side of the spectrum, your body can also choose to slow down the conversion and put energy into more important bodily function in instances where you may be critically ill. There was a study where they reduced conversion in people who are critically ill, those in the hospital, people taking certain medications and so on.
More recently, we also see some patients with obesity and metabolic syndrome with lower than normal T3 levels due to a slowing of peripheral thyroid conversion. In this way, thyroid conversion is becoming a more important topic because it influences how Doctors should treat and evaluate certain patients. This regulation is one of the most important concepts to understand in thyroid physiology.
Thyroid conversion occurs nonstop, and occurs in major tissues such as your liver, your gastrointestinal tract but it also occurs in each cell. T3 the thyroid hormone floats around in your blood-stream until it hits the target cell.
Once there it can activate cellular function in two important ways, the first is through non-genomic changes in the cell. include direct impact in enzymes and transporters on the surface of the cell itself. An example would be the way that T3 activates calcium channels in the heart which may cause palpitations when ingested. Many thyroid disorders can affect one in many ways due to how the thyroid is a multi-functional organ, and the majority of thyroid hormone produced by the endocrine system is essential to our bodies , one small enzyme off-target and the whole hormone is off balance. It is good to take care of our bodies in order to keep it under control for as long as possible.
Resistance to Thyrotropin