Neuroendocrine Regulation of Fluid Intake and Homeostasis

Body fluids provide the matrix in which the biochemical reactions that comprise cellular metabolism occur. The concentration of substrates in the cellular fluid is a major factor that determines the rate at which these reactions occur. Furthermore, all body tissues depend on the circulation of blood to provide the nutrients needed to support cellular metabolism and to carry away metabolites for excretion. Thus, the maintenance of concentrations of solutes, or osmolalities (osmotic homeostasis), and the regulation of volumes of the various body fluid compartments (volume homeostasis) are critical functions for normal physiology in all animals.