TSH- Thyroid-stimulating hormone

Here is the link to my podcast. https://docs.google.com/file/d/0B0n3ho2c-P5jakV1MldvbVVhVFE/edit

Transcript:

"Hello, my name is Blake Williams and in this podcast I will be teaching you about TSH, otherwise known as Thyroid-stimulating hormone. First of all, TSH is produced in the Anterior Pituitary Gland, and its function is that it stimulates the thyroid gland to produce thyroid hormones, such as T₃ and T₄. Those thyroid hormones are responsible for controlling the body’s metabolism. The production of T₃ and T₄ is controlled by a negative feedback loop based on the levels of these two thyroid hormones. When the levels are too low, for example, receptors on the plasma membrane of thyroid follicular cells send signals to the brain, specifically to the hypothalamus. The hypothalamus produces TRH, or Thyroid-releasing hormone, that travels to the Anterior Pituitary Gland and stimulates the production TSH. The TSH then binds to a TSH receptor on a thyroid cell, stimulating the production of T₃ and T₄. This system, in which the nervous system stimulates the endocrine system, is known as a neuroendocrine pathway.

It is good to take note that TSH production is regulated by the hypothalamus, and the TRH it releases. For example, if the concentrations of the thyroid hormones are too high, the hypothalamus will not send TRH to stimulate the production of TSH. Only once the concentrations of the thyroid hormone reach lower levels will the hypothalamus allow TSH to start producing again.

The last feature of TSH that I will talk about is that it is water-soluble. There is a big difference between water-soluble and fat-soluble hormones. Water-soluble hormones bind to receptors on the cell membranes, whereas lipid soluble hormones diffuse through the plasma membrane and bind with receptors on the inside of the cell. Also, fat-soluble hormones contain cholesterol, whereas water-soluble hormones do not."

References:



Benderson, Joshua B. "What is the function of thyroid-stimulating hormone (TSH) in the body?."    
          sharecare. 2014. http://www.sharecare.com/health/endocrine-system/what-function-tsh-in-body

"Thyroid Hormones (T3/T4)." Heal Yourself At Home. 2014.
          http://healyourselfathome.com/SUPPORTING_INFORMATION/CELL_
          MESSENGERS/HORMONES/AMINES/TH/t3_and_t4.aspx

"Thyroid stimulating-hormone." Wikipedia. 2014. http://en.wikipedia.org/wiki/Thyroid-
          stimulating_hormone