These studies can also provide new avenues for restoring populations of endangered species, for limiting noxious organisms and for clarifying the effects of endocrine-disrupting chemicals. These chemicals enter the environment through human activity. Their negative impact on marine animals, including fish, can be profound because hormones play a crucial role in controlling development. The regulation of salt and water balance is a fundamental requirement of life. The structure and function of macromolecules depend closely on their interactions with water and its solutes.
Few factors affect the distribution and evolution of an organism as extensively as osmoregulation.
Thus, organisms invest considerable energy in controlling precisely the composition of both intracellular and extracellular fluids. Osmotic equilibrium is maintained only through the precise interplay of a major portion of the neuroendocrine array. Indeed, the maintenance of osmotic balance in seriously ill patients is among the most difficult challenges in medicine. In view of the cost and importance of osmoregulation, it may seem ironic that the mechanisms that monitor and regulate osmotic balance are so poorly understood. Closer attention reveals the impediment, the typically complex structure and arrangement of osmoreceptive cells and tissues.