Tropic hormone

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Tropic hormones are hormones that have other endocrine glands as their target. Most tropic hormones are produced and secreted by the anterior pituitary.[1] The hypothalamus secretes tropic hormones that target the anterior pituitary, and the thyroid gland secretes thyroxine, which targets the hypothalamus and therefore can be considered a tropic hormone.[2]

The term tropic is from Ancient Greek τροπικός (tropikós), in the sense "of or pertaining to a turn or change", meaning "causing a change, affecting"; this is the same origin as tropic and trope. This should not be confused with trophic, as in similar-sounding trophic hormone – the words and concepts are both unrelated.[3] Tropic hormones are contrasted with non-tropic hormones, which directly stimulate target cells.

Examples[edit]

Anterior pituitary[edit]

Tropic hormones from the anterior pituitary include:

Hypothalamus[edit]

In turn, the hypothalamus controls the release of hormones from the anterior pituitary by secreting a class of hypothalamic neurohormones called releasing and release-inhibiting hormones—which are released to the hypothalamo-hypophyseal portal system and act on the anterior pituitary.[9]

See also[edit]

References[edit]

  1. ^ Purves, William K.; David Sadava; Gordon H. Orians; H. Craig Heller (2001). Life: The Science of Biology (6th ed.). Massachusetts: Sinauer Associates. p. 719. ISBN 0-7167-3873-2. 
  2. ^ Cambell, Neil A.; Jane B. Reece. Biology (6th ed.). Sinauer Associates. ISBN 0-321-27045-2. 
  3. ^ Steinberg, Werner (1952). "Trophic Vs. Tropic". Journal of the American Medical Association 149: 82. doi:10.1001/jama.1952.02930180084027.  edit
  4. ^ Purves et. al. p. 718.
  5. ^ Purves et. al. p. 718.
  6. ^ Purves et. al. p. 718.
  7. ^ Purves et. al. p. 718.
  8. ^ Cambell, Neil A.; Jane B. Reece. Biology (6th ed.). Sinauer Associates. ISBN 0-321-27045-2. 
  9. ^ Purves et. al. p. 720–721.