Thyrotropin releasing hormone (TRH) is secreted by hypothalamus region of the brain. The main function of thyrotropin is stimulation of pituitary gland for secretion of thyroid stimulating hormone (TSH). Thyroid stimulating hormone instructs the thyroid gland to produce and release varied kinds of thyroid hormones. TSH also contributes to better functioning of the thyroid gland. It can thus be said that thyrotropin plays a vital role in regulation of the functions of the thyroid gland.
Reduction in thyroid hormone levels in the body is identified by the brain. Subsequently, the hypothalamus releases thyrotropin hormone into the bloodstream of the pituitary gland, which triggers increased production of TSH by the gland and subsequent stimulation of thyroid gland for higher production of thyroid hormones. It can thus be said that the levels of thyrotropin are dependent on the levels of thyroid hormones.
The varied hormones produced by thyroid gland assist in management and regulation of vital body functions like heart rate, body temperature, neuromuscular functioning, and heat generation, etc. It is therefore very important to know and study thyrotropin levels.
Functions and other aspects of thyrotropin levels
- Thyrotropin structure consists of a small chain of three amino acids. It is thus one of the smallest-sized hormones found in human body.
- Thyrotropin is situated at the skull’s base in the hypothalamus area of brain. It consists of a group of nerve cells called paraventricular nucleus. The nerve fibers that come out from hypothalamus supply TRH into the pituitary gland’s surrounding blood vessels. Thyrotropin then carries out its primary function of controlling the generation and release of thyroid stimulating hormone by the gland. TSH then regulates the secretion of thyroid hormones.
- Thyrotropin also helps stimulate the pituitary gland in the process of prolactin hormones secretion.
- Thyrotropin can also be found in different nervous system tissues where it functions as a brain chemical or neurotransmitter. For e.g., thyrotropin injections activate the feeding and arousal parts of the brain and thus promotes appetite and alertness.
- Thyrotropin has a very short lifespan; it is less than 2 minutes. It passes in the bloodstream to the pituitary gland for a distance of approximately 1 inch and then gets broken down.
Normal levels of thyrotropin
Thyrotropin levels vary as per the levels of TSH. Normal thyrotropin levels or normal levels of TSH are discussed below:
- Normal thyrotropin levels in adult males and females are usually between 0.5 mIU/L and 4.5 mIU/L (mIU/L = milli-international units per liter).
- Normal thyrotropin levels are in children are comparatively higher. They usually fall in the range between 3 mIU/L and 18 mIU/L.
Pregnancy and normal thyrotropin levels
Pregnant women as well as those who want to get pregnant should know the importance of keeping track of thyrotropin levels during the entire tenure of pregnancy. It may be noted that abnormal thyrotropin levels during pregnancy can result in several complications in the unborn baby and/or mother.
Presented below is information about normal thyrotropin levels/normal TSH levels during each of the 3 trimesters:
- It falls in range of 0.25 mIU/L and 2.96 mIU/L in the 1st trimester
- It falls in range of 0.25 mIU/L and 2.96 mIU/L in the 2nd trimester
- It falls in range of 0.42 mIU/L and 2.76 mIU/L in the 3rd trimester
High and low thyrotropin levels
Elevated TSH or thyrotropin levels can cause hyperthyroidism, while low levels of thyrotropin or TSH may cause hypothyroidism. Both are serious conditions and need to be medically treated.
Common hyperthyroidism symptoms are as follows:
- Poor or anomalous discharge during menstrual cycles
- Puffy eyes
- The upper eyelids in female patients tend to be at an abnormally higher level, thereby imparting them a distinctive staring appearance.
- Fatigue, high rate of heartbeat, frequent and persistent bowel movements, increased sweating, weight loss, tremors, irritability, and inattentiveness
Common hypothyroidism symptoms are as follows:
- Physical problems such as achy, tender, weak, and stiff muscles; increased weight; puffed up eyes; deep, hoarser voice; exhaustion; swollen, painful, and stiff joints including wrist pain; pale, dry, coarse skin; immune system issues; high blood cholesterol; numb hands; loss of hair; hypersensitivity to cold; menstruation issues; diminished metabolism; and chills, trembles, and shivers.
- Cognitive issues like nervousness, depression, and diminished thinking capabilities which may occur along with additional cognition problems like forgetfulness, loss of memory, and/or dementia.
- Digestive system anomalies such as abnormal bowel movements, poor appetite, and/or constipation
Treatment of abnormal thyrotropin levels
Treatment of hyperthyroidism or elevated TSH/thyrotropin levels is as follows:
- Regulation of thyroid hormone levels via anti-thyroid drugs and/or oral radioactive iodine
- Severe cases may require surgical removal of the thyroid gland. Subsequently, patients need to go for hormone replacement therapy (HRT) for the rest of their lives.
Treatment of hypothyroidism or low TSH/thyrotropin levels is as follows:
- Hormone replacement therapy
- Intake of a healthy diet, nutritional supplements, lifestyle changes, and regular exercising. This is also recommended for patients with elevated TSH/ thyrotropin levels.
Filed in: Diagnosis