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.
Two such hormones are secreted by the anterior pituitary gland: follicle-stimulating hormone and luteinizing hormone, both of which are active, but with differing effects, in the two sexes. Called also gonadotropic hormone. chorionic gonadotropin (human chorionic gonadotropin (HCG) (hCG)) 1. a glycopeptide hormone that is produced by cells of the fetal placenta and maintains the function of the corpus luteum during the first few weeks of pregnancy.