RT Book, Section A1 Parker, Keith L. A1 Schimmer, Bernard P. A2 Brunton, Laurence L. A2 Chabner, Bruce A. A2 Knollmann, Björn C. SR Print(0) ID 1127869134 T1 Introduction To Endocrinology: The Hypothalamic-Pituitary Axis T2 Goodman & Gilman's: The Pharmacological Basis of Therapeutics, 12e YR 2015 FD 2015 PB McGraw-Hill Education PP New York, NY SN 9780071624428 LK accesspharmacy.mhmedical.com/content.aspx?aid=1127869134 RD 2022/05/29 AB Endocrinology analyzes the biosynthesis of hormones, their sites of production, and the sites and mechanisms of their action and interaction. The term hormone is of Greek origin and classically refers to chemical messengers that circulate in body fluids and produce specific effects on cells distant from their point of origin. The major functions of hormones include the regulation of energy storage, production, and utilization; the adaptation to new environments or conditions of stress; the facilitation of growth and development; and the maturation and function of the reproductive system. Although hormones were originally defined as products of ductless glands, we now appreciate that many organs that were not classically considered as "endocrine" (e.g., the heart, kidneys, GI tract, adipocytes, and brain) synthesize and secrete hormones that play key physiological roles; many of these hormones are now employed either diagnostically or therapeutically in clinical medicine. In addition, the field of endocrinology has expanded to include the actions of growth factors acting by means of autocrine and paracrine mechanisms, the influence of neurons—particularly those in the hypothalamus—that regulate endocrine function, and the reciprocal interactions of cytokines and other components of the immune system with the endocrine system.