Thyrotropin Levels

TRH (thyrotropin releasing hormone) or Thyrotropin is a hormone produced by hypothalamus in the brain. Its main function is to stimulate the pituitary gland to release TSH or thyroid stimulating hormone. TSH, in turn, plays a vital role in release and functioning of different kinds of thyroid hormones by the thyroid gland. Thus, thyrotropin hormone is responsible for efficient management and regulation of thyroid gland functions.

Any dip in the levels of thyroid hormones is detected by the brain which then triggers release of thyrotropin by the hypothalamus into pituitary gland’s bloodstream. Subsequently additional amounts of TSH are secreted by the gland which then stimulates the thyroid gland to make more thyroid hormones. Thus, thyrotropin levels are dependent on levels of TSH and thyroid hormones in the body.

It may be noted that the different hormones secreted by thyroid gland help in regulation and control of different vital functions of body like body temperature management, heart rate, metabolic rate, heat production, and neuromuscular function, etc. Hence, the study of thyrotropin levels in body is very important.

Thyrotropin levels functions and more

• Thyrotropin hormone is made of a tiny chain composed of just 3 amino acids. Thus, it is one of the smallest hormones in humans. Located in the hypothalamus at the base of skull, TRH has a set of nerve cells known as the paraventricular nucleus.
• The nerve fibers coming out from hypothalamus transfer thyrotropin to the blood surrounding the pituitary gland. Here, the hormone performs its main function of regulating the production and release of TSH by the pituitary gland. TSH then contributes towards secretion and release of varied thyroid hormones.
• Thyrotropin is also present across the tissues of the nervous system where it often acts and functions as a neurotransmitter. For example, TRH injections affect the arousal and feeding areas of brain and have an effect on alertness and appetite levels.
• TRH also plays a part in stimulation of pituitary gland and subsequent release of prolactin hormones.
• The lifespan of thyrotropin is very short and lasts for under two minutes. It flows across blood for a distance of about an inch to the pituitary gland and then gets processed or broken down.

Normal thyrotropin levels

As discussed above thyrotropin levels vary and are dependent on the levels of thyroid stimulating hormones.

• Normal TSH or thyrotropin levels in men and women tend to fall in the range of 5 mIU/L (milli-international units per liter) and 4.5 mIU/L.
• In children, normal TSH or thyrotropin levels are much higher and typically occur between 3 mIU/L and 18 mIU/L.

Normal thyrotropin levels during pregnancy

Women who are expecting or are trying to become pregnant have to be aware of their TSH or thyrotropin levels at all times and phases of pregnancy. Abnormal levels of TSH can cause many health complications (like premature delivery) in the mother and/or the unborn child. Listed below are the normal thyrotropin levels during pregnancy, categorized as per the 3 trimesters:

• In first trimester, it varies between 0.25 mIU/L and 2.96 mIU/L
• In second trimester, it varies between 0.25 mIU/L and 2.96 mIU/L
• In third trimester, normal TSH or thyrotropin level varies between 0.42 mIU/L and 2.76 mIU/L.

Thyrotropin levels – Low and High levels

Higher than normal thyrotropin levels can cause hyperthyroidism, while lower than normal TSH levels may cause hypothyroidism. Both conditions are serious and require medical treatment.

Some common symptoms of hyperthyroidism include

• In women, the upper eyelids may rise up to a higher than normal level, thereby making the patient appear as if she is staring. Puffy eyes may also be present
• Abnormal or poor menstruation discharge
• Fatigue, increased heartbeat rate, chronic bowel movements, weight loss, excess sweating, tremors, distractible, and/or increased irritability.

Some common symptoms of hypothyroidism include

• Physical symptoms like aches, weakness, tenderness, and stiffness of muscles; puffy eyes; weight gain; hoarser or deeper voice; tiredness; pale, coarse, dry skin; pain in wrist; joint pain, swelling, and stiffness; elevated blood cholesterol; immune system problems; numbness in hands; hair loss; increased cold sensitivity; reduced metabolic rate; menstrual problems; and trembling, chills, and shivering.
• Digestive problems like abnormal stool, appetite loss, and/or constipation
• Cognitive problems like depression, nervousness, and reduced thinking capacities that may be accompanied by forgetfulness, memory loss, and/or dementia.

Abnormal thyrotropin levels Treatment

• Low thyrotropin levels or hypothyroidism treatment includes hormone replacement therapy (HRT) for the lifetime of the patient.
• Low thyrotropin levels or hyperthyroidism treatment includes use of oral radioactive iodine and/or anti-thyroid drugs that help control the levels of TSH or thyroid hormones. In severe cases, doctors may surgically remove the thyroid gland; patients need to undergo HRT for the rest of their lives after surgery.
• In both cases, doctors also recommend diet changes, nutritional supplements, regular exercising, and lifestyle changes.