Now, we just said that the Releasing Hormones from the hypothalamus cause the release of hormones in the adenohypophysis. These are the releasing hormones coming from the hypothalamus:
- Corticotropin Releasing Hormone (CRH causes the release of ACTH)
- Thyrotropin Releasing Hormone (TRH causes the release of TSH;Thyroid Stimulating Hormone;Thyrotropin)
- Gonadotropin Releasing Hormone (GnRH releases LH and FSH.)
- Growth Hormone R.H. & Growth Hormone I.H.
- Prolactin R.H. & Prolactin I.H.
Now we explore what hormones are secreted by the adenohypophysis (as a result of the Releasing Hormones secreted by the hypothalamus).
These releasing hormones above cause the adenohypophysis to release the following 6 hormones:
- Growth Hormone
- Thyrotropin (Thyroid Stimulating Hormone; TSH)
- AdrenoCorticoTropin Hormone (ACTH)
- Luteinizing Hormone (LH)
- Follicle Stimulating Hormone (FSH)
We have 6 hormones listed above. Four of them are considered tropic hormones and two are not tropic. Tropic means they affect other endocrine glands. (The model of ALL tropic hormones is a NEGATIVE FEEDBACK LOOP.)
1 & 2) The two that are not tropic are Growth Hormone (affects bone/muscles) and Prolactin (affects mammary glands). Why? Because mammary glands are not endocrine glands, they secrete milk out the breast. Since GH and Prolactic are not tropic hormones, they don’t create a feedback loop, like all the others do.
We will talk about growth hormone and prolactin in further detail, but before we do that, let’s talk about something more important and clinically relevant: Thyrotropin.