Publisher Summary This chapter discusses the functional morphology of teleost gonads. Information presented in this chapter indicates that there are several processes of germ cell development, which are closely associated with changes in cellular activities of somatic cell elements. Recent studies on biochemical aspects of vitellogenesis in teleosts have shown that the hepatic and ovarian yolk proteins are similar to those of amphibian species. An in vitro method involving the separation of the follicular components has facilitated investigations of the detailed mechanism of the production of two major follicular steroid hormones. As a result of the usage of this technique, a two cell-type model involving thecal and granulosa cell layers has been proposed for the production of these two steroids for the first time in lower vertebrates. With further refinements this well characterized incubation procedure should provide an excellent system for studying the molecular basis of the mechanism of gonadotropin action on follicular steroidogenesis.

6 The Functional Morphology of Teleost Gonads

Comparative endocrinology is one of the most rapidly developing subdis ciplines within the field of endocrinology, and it is having a significant impact on research at the molecular, cellular, organisma1 and environmental levels. Much of the current ferment in endocrinology is in reproductive endocrinology. The purpose of this volume on hormones and reproduction in fishes, amphibians and reptiles is to summarize our present understandings and to identify important research problems to be addressed in the area of comparative reproductive endocrinology. It was inspired by the gathering at Copper Mountain, Colorado, of eminent endocrine scientists from around the world on the occasion of the Tenth International Symposium on Comparative Endocrinology in July, 1985. While preparing for that meeting, we decided that a special volume on reproductive endocrinology was needed to summarize what is known and to stimulate research in particular directions. Why do we emphasize fishes, amphibians and reptiles? First, knowledge about the reproductive endocrinology of these ectothermic vertebrates can provide a clearer picture of the evolution of reproductive hormones and their effects on target organs. This comparative approach can lead to new theories about the evolution of reproductive control mechanisms. Second, studies concerning the reproductive endocrinology of "lower" vertebrates can result in development of "model systems" for application to studies of birds and mammals. Indeed, information about the patterns of reproductive control in ectothermic vertebrates can tell us which are evolutionarily stable and which are labile."

/pdf/hormones-and-reproduction-in-fishes-amphibians-and-reptiles-41bjvyyu4l.pdf

Hormones and reproduction in fishes, amphibians, and reptiles

The biology and use of zebrafish brachydanio rerio in fisheries research a literature review

Sex reversal in salmonid culture

Steroids in the plasma of the winter flounder (Pseudopleuronectes americanus walbaum). A seasonal study and investigation of steroid involvement in oocyte maturation

T. H. Simpson

Papers

Steroid biosynthesis in the testis of dogfish (squalus acanthias).

Steroids in the semen of dogfish (squalus acanthias).

Sex hormones in fish. The oestrogens of cod (Gadus callarias).

Sex hormones in fish. ii. the oestrogens of scyliorhinus caniculus.

Steroid biosynthesis in vitro by the component tissues of the ovary of dogfish (Scyliorhinus caniculus L.).