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.
The pituitary gland produces LH (luteinising hormone) and FSH (follicle stimulating hormone) which stimulate the gonads in two ways: FSH stimulates growth of the sex cells, the ovarian follicles in a woman, the seminiferous tubules and early stages of sperm production in a man.