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The term trophic is from Ancient Greekτροφικός (trophikós) meaning "pertaining to food or nourishment", here used to mean "growth"; this is the same origin as atrophy. This should not be confused with tropic, as in the similar-sounding tropic hormone – the words and concepts are both unrelated.
Tropic hormones are hormones that have other endocrine glands as their target. Most tropic hormones are produced and secreted by the anterior pituitary. [1]: 719 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.
The main release-inhibiting hormones or inhibiting hormones are as follows: The hypothalamus uses somatostatin to tell the pituitary to inhibit somatotropin and to tell the gastrointestinal tract to inhibit various gastrointestinal hormones. There are various other inhibiting factors that also have tropic endocrine inhibition activity.
Fig.1: Various tropic cues interact to guide the growth cone; the initial role of these cues was identified as either repulsive (red) or attractive (green). The growth cone is a highly dynamic structure of the developing neuron , changing directionality in response to different secreted and contact-dependent guidance cues; it navigates through ...
A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. [1] Usually it is a secreted protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes. Growth factors typically act as signaling molecules ...
The hypothalamus regulates the hormonal output of the anterior pituitary and creates two hormones that it exports to the posterior pituitary for storage and later release. Four of the six anterior pituitary hormones are tropic hormones that regulate the function of other endocrine organs. Most anterior pituitary hormones exhibit a diurnal ...
Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. [1] It is also used as a medication and diagnostic agent .
Lymphocytes can enter mitosis when they are activated by mitogens or antigens. B cells specifically can divide when they encounter an antigen matching their immunoglobulin . T cells undergo mitosis when stimulated by mitogens to produce small lymphocytes that are then responsible for the production of lymphokines , which are substances that ...