Hormones have a manifold impact upon growth and metabolism. This book focuses upon the molecular biology of fish hormones and their regulation. Chapters dealing with gonadotropin, corticotropin, vasotocin, isotocin, somatolactin, and other hormones are written by an international team of fish physiologists and endocrinologists. In addition, there are chapters that survey a growing literature on the ways hormones are regulated both in terms of their actions and in terms of the gene transcription that leads to their formation. The first two sections of the book covers brain and pituitary hormones and the latter two sections are devoted to other hormones and their regulation. As more and more endocrinologists and physiologists seek to use hormones that are inexpensive, provide for more facile experimental replication, and are less subject to cumbersome regulation, they will turn to the sorts of fish models reviewed in this book.