ABSTRACT
This chapter seeks to provide insight into how advances in cellular and molecular techniques have been, and can be, applied to further understanding of fish osmoregulation. The maintenance of salt and water balance in fish is the consequence of a tightly regulated, integrated network of molecular and cellular processes operating within a variety of cell types and across a range of tissues. Osmoregulatory hormones may have distinct effects, depending on circulating concentrations, and their impact may vary with the presence of other circulating mediators, as well as the molecular and cellular wiring of the target cell. The yolk ball offers several advantages over the isolated yolk sac membrane in terms of its usefulness as a model system for the examination of osmoregulation. In the few studies where piscine cell lines have been utilized to investigate aspects of cellular ion and water transport, further potential difficulties have emerged.
