1 The phenotype may change constantly throughout the life of an individual because of environmental changes and the physiological and morphological changes associated with aging.
One special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones. hormone (from Greek á½ÏÎ¼Î®, impetus) is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.
An example of a smaller peptide hormone is TSH (thyroid stimulating hormone) and a larger peptide hormone is insulin. Other peptide hormones of honorable mention are prolactin (aids in lactation), growth hormone and vasopressin (water regulation), which are produced by the pituitary gland. Another, less commonly known example, is atrial natiuretic peptide (ANP), which is produced by the heart.