Some whys and wherefores in fish endocrinology?

Endocrinology has considerably expanded its field in recent years and many mechanisms of regulation in biology involve hormone related factors (biochemical mediators) which can be found in all living organisms. Endocrinology has provided powerful tools to understanding the regulation of many functions in fish and other animals. The various models seen in the composite group of fish permit fruitful comparisons with those in other groups of vertebrates and allow these to be placed into an evolutionary perspective. Applications to medical sciences have been derived from work originally carried on in fish endocrinology and several concepts developed on mammals and higher vertebrates were useful for research on fish. Endocrinology has had a major impact on the knowledge of many aspects of fish biology, such as reproduction, osmoregulation, stress, growth, and pathology, with application to fish farming. It has provided conceptual and technical tools for the control of several functions of some cultivated species and has contributed to the efficient domestication of several fish species.