Melatonin. Multifunctionality. Fish.

This review presents data both on general patterns of melatonin (MT) functioning in vertebrates and its features specific to fish. The topography of MT secretion, mechanisms of its synthesis, types of MT receptors, as well as its effects on the immune and antioxidant systems and water–salt balance are described. A special focus is on MT-related processes of fish reproduction, growth and nutrition. The effect of MT on the key aspects of neuroendocrine regulation of fish feeding is discussed. It is shown that MT, as a main endogenous synchronizer of physiological processes, plays a crucial role in the central and peripheral regulation of various physiological functions, adapting them to environmental conditions. [ABSTRACT FROM AUTHOR]