Tropic hormone
Template:Short description Template:Distinguish Tropic hormones are hormones that have other endocrine glands as their target. Most tropic hormones are produced and secreted by the anterior pituitary.<ref name=Purves>Template:Cite book</ref>Template:Rp 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.<ref name=Cambell> Template:Cite book </ref>
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.<ref>Template:Cite journal</ref> Tropic hormones are contrasted with non-tropic hormones, which directly stimulate target cells.
Examples
Anterior pituitary
Tropic hormones from the anterior pituitary include:
- Thyroid-stimulating hormone (TSH or thyrotropin) – stimulates the thyroid gland to make and release thyroid hormone.<ref name=Purves/>Template:Rp
- Adrenocorticotropic hormone (ACTH or corticotropin) – stimulates the adrenal cortex to release glucocorticoids.<ref name=Purves/>Template:Rp
- Luteinizing hormone (LH) – stimulates the release of steroid hormones in gonads—the ovary and testes.<ref name=Purves/>Template:Rp
- Follicle-stimulating hormone (FSH) – stimulates the maturation of eggs and production of sperm.<ref name=Purves/>Template:Rp<ref name=Cambell/>
Hypothalamus
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.<ref name=Purves/>Template:Rp