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.
Understanding the TRH Test. To understand how the TRH Stimulation Test works, it's first helpful to quickly review how the various brain hormones interact with the thyroid. Your hypothalamus is a gland in your brain that secretes thyrotropin-releasing hormone (TRH). When TRH is released, it stimulates your pituitary gland -- also in the brain -- to release thyroid stimulating hormone (TSH). TSH stimulates the thyroid itself to make thyroid hormones.