ANATOMY & PHYSIOLOGY BIOCHEMISTRY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site hormone A substance that is produced in tiny amounts in one part of an organism and is transported to other parts where it has a definite physiological effect. They also often affect the functioning of other hormone-producing tissues so that the effects can be complex and integrated. Hormones influence the rate at which reactions proceed. They are important in both animals and plants. Hormones do not fall into any one particular chemical class. They may be steroids, peptides, or relatively simple compounds such as adrenaline. In animals, hormones are usually secreted by endocrine glands directly from gland cells into the bloodstream, where they often circulate in combination with serum proteins. They occur copiuously in vertebrates but are also known in some invertebrates. Plant hormones, called phytohormones (e.g. auxins, play a prominent role in plant growth. Principal hormones in the human body Hormone Chemical type Secreting gland Target adrenaline modified amino acid adrenal medulla heart adrenocorticotropic hormone polypeptide anterior pituitary adrenal cortex androgen steroid testes many tissues antidiuretic hormone peptide hypothalamus kidneys atrial natriuretic peptide peptide heart kidneys calcitonin peptide thyroid peptide cholecystokinin peptide lining of small intestine pancreas corticotropin-releasing hormone peptide hypothalamus anterior pituitary dopamine peptide hypothalamus anterior pituitary enterogastrone polypeptide lining of small intestine stomach estrogen steroid ovaries uterus follicle-stimulating hormone glycoprotein anterior pituitary gonads gastrin peptide stomach lining stomach glucagon protein pancreas liver glucocorticoid steroid adrenal cortex muscles gonaotrophin-releasing hormone peptide hypothalamus anterior pituitary growth hormone protein anterior pituitary bones growth hormone-releasing hormone peptide hypothalamus anterior pituitary insulin protein pancreas muscles luteinizing hormone glycoprotein anterior pituitary gonads melanocyte-stimulating hormone peptide anterior pituitary melanocytes melatonin modified amino acid pineal gland hypothalamus mineralocorticoid steroid adrenal cortex kidneys noradrenaline modified amino acid adrenal medulla heart oxytocin peptide hypothalamus uterus parathyroid hormone protein parathyroid bones progesterone steroid ovaries uterus prolactin protein anterior pituitary mammary glands prostaglandin modified fatty acid many tissues many tissues secretin peptide lining of small intestine pancreas somatostain peptide pancreas gastrointestinal tract thymosin peptide thymus white blood cells thyroid-stimulating hormone glycoprotein anterior pituitary thyroid thyrotropin-releasing hormone peptide hypothalamus anterior pituitary thyroxine iodinated amino acid derivative thyroid many tissues vitamin D sterol skin bones Related categories    • BIOCHEMISTRY    • ANATOMY AND PHYSIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP