What is the Difference Between TSH and TRH

The main difference between TSH and TRH is that TSH (thyroid stimulating hormone) regulates the production of hormones by the thyroid gland whereas TRH (thyroid releasing hormone) stimulates the pituitary gland to produce and release TSH.

TSH and TRH are two thyroid hormones involved in the production and release of thyroid hormones. The thyroid gland produces thyroxine (T4), and then triiodothyronine (T3).

Key Areas Covered

1. What is TSH
    – Definition, Structure, Function
2. What is TRH
    – Definition, Structure, Function
3. Similarities Between TSH and TRH
    – Outline of Common Features
4. Difference Between TSH and TRH
    – Comparison of Key Differences

Key Terms

TRH, TSH, Thyroid 

What is TSH

TSH (thyroid stimulating hormone) is the pituitary hormone whose function is to stimulate the thyroid gland to produce thyroid hormones. Generally, the thyroid gland produces two hormones: thyroxine (T4) and triiodothyronine (T3). The main function of the two hormones is to stimulate the metabolism of each and every tissue. TSH is a glycoprotein in structure and is produced by the thyrotrope cells of the anterior pituitary gland. Moreover, the TSH glycoprotein has two subunits; the alpha and the beta subunit.

Figure 1: TRH

Furthermore, TSH regulates the levels of the T4 and T3 hormones in the bloodstream. The secretion of TSH occurs throughout life and it reaches high levels in periods of rapid growth and development. In addition, the levels of TSH release are high in the response to stress.  

What is TRH

TRH (thyroid-releasing hormone) is the hormone produced by the neurons of the hypothalamus. The main function of TRH is to release two hormones from the anterior pituitary gland. They are TSH and prolactin. The main function of TSH, on the other hand, is to regulate the blood levels of thyroid hormones and to regulate their production and release. In addition, prolactin is responsible for milk production.

Figure 2: Thyroid Function

Moreover, TRH is a tripeptide hormone produced by the paraventricular nucleus, a nerve cell cluster. The nerve fibers carry the hormone to the bloodstream. In general, this regulates the production and secretion of TSH hormone in the pituitary gland. However, TSH has a very short life, lasting for two minutes, and traveling a less distance around two inches in the bloodstream.

Similarities Between TSH and TRH

• TSH and TRH are two types of hormones produced by the brain.
• The main function of both hormones is to stimulate the production and secretion of thyroid hormones.

Difference Between TSH and TRH

Definition

TSH (thyroid stimulating hormone) refers to a hormone secreted by the pituitary gland, which regulates the production of thyroid hormones, while TRH (thyroid releasing hormone) refers to a hormone secreted by the hypothalamus, which regulates the production of TSH.

Type of Hormone

TSH is a glycoprotein hormone while TRH is a tripeptide hormone.

Production

Moreover, TSH is produced by thyrotrope cells in the anterior pituitary gland while TRH is produced by the neurons in the hypothalamus.

Function

TSH regulates the production of hormones by the thyroid gland while TRH stimulates the pituitary gland to produce and release TSH.

Conclusion

In brief, TSH and TRH are two hormones produced by the brain in humans. The main function of both hormones is to regulate the production of thyroid hormones. TSH or thyroid stimulating hormone is produced by the anterior pituitary gland in the brain. It is also a glycoprotein hormone responsible for the regulation of the production of thyroid hormones from the thyroid gland. TRH or thyroid-releasing hormone, on the other hand, is a tripeptide hormone produced by the hypothalamus. In addition, the main function of the TRH is to stimulate the pituitary gland to produce TSH. Therefore, the main difference between TSH and TRH is their function.

References:

1. “TSH (Thyroid-Stimulating Hormone) Test: Medlineplus Medical Test.” MedlinePlus, U.S. National Library of Medicine
2. “Thyrotropin-Releasing Hormone.” You and Your Hormones,

Image Courtesy:

1. “Thyrotropin-releasing hormone” By Fvasconcellos – Own work (Public Domain) via Commons Wikimedia
2. “Thyroid system” By Mikael Häggström – Own Work (Public Domain) via Commons Wikimedia