Thyroid stimulating hormone is a hormone that the pituitary gland produces and it is very important for the proper functioning of the thyroid gland. The thyroid gland is responsible for production of two important hormones T4 and T3, both of which are essential for the functioning of many systems in the body. Calcitonin is another hormone that the thyroid gland produces and it has the role of maintaining the normal levels of calcium in the body.
The hypothalamus in the brain and the pituitary gland are responsible for the functioning of the thyroid gland. The hypothalamus produces thyrotropin-releasing hormone, abbreviated TRH. This hormone stimulates the pituitary gland to make the thyroid stimulating hormone or TSH, which controls the production of T4 and T3 in the thyroid gland.
Thyroid gland disorders
The two main problems of the thyroid gland are hyperthyroidism and hypothyroidism. Hyperthyroidism or overactive thyroid gland is a condition marked by increased production of thyroid hormones. People with this problem are very likely to experience weight loss, rapid heart rate, diarrhea and nervousness. On the other side, hypothyroidism or inactive thyroid gland is a condition marked by deficiency of the thyroid hormones and the people who suffer from this condition may have symptoms like weight gain, constipation, dry skin and fatigue.
TSH blood test
The functioning of the thyroid gland can be checked by measuring TSH levels in the blood. The level of this hormone that is regarded as normal ranges between 0.5 and 5.5 in certain countries, but there are countries in which this level ranges between 0.3 and 3.3. However, the fact is that TSH does not have the same level all the time. There are differences in its levels during night and day and the difference between the lowest and highest levels of TSH may be even 2 points.
When the level of TSH is low, it indicates the increased activity of the thyroid gland, which makes this one of the inevitable symptoms of hyperthyroidism. Quite the opposite goes for high level of this hormone which is the main indicator of hypothyroidism.
Having in mind the fact that the thyroid stimulating hormone is produced by the pituitary gland and not by the thyroid gland, it is important to know that there are cases when the thyroid gland functions well while the pituitary gland, which is controlled by hypothalamus in the brain, malfunctions due to some reasons. This is why besides the tests that check the levels of T3 and T4, the tests that check the levels of TSH should also be performed.