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.
What is parathyroid hormone? Parathyroid hormone is secreted from the four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low.It does this through its actions on the kidneys, bones and intestine:hat is parathyroid hormone? Parathyroid hormone is secreted from the four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low.
Hormonal Regulation of Hormone Release. Hormonal regulation of hormone release involves a hormone binding to its receptor on an endocrine cell to regulate hormonal secretion. A hormone that stimulates hormone secretion is called a tropic hormone. Tropic hormones may also stimulate proliferation of endocrine cells.or polar hormones, tropic hormones stimulate endocrine secretion by stimulating cell secretion; that is, exocytosis. An example is the regulation of growth hormone (GH) secretion by the tropic hormone growth hormone releasing hormone (GHRH) . GHRH is a hypophysiotropic hormone.