Abstract
Leptin has an important function in mammals, regulating appetite and energy balance. However, the physiological role of leptin in fish is virtually unknown, as the existence/structure of fish leptin has until recently been unknown. We have raised salmon leptin antibodies, and thereby established homologous, proteomic research tools; including the first ever fish leptin RIA. This allows for a three-way research approach: 1. Identify leptin-producing tissues by IHC. 2. Examine circulating leptin levels, tissue content, in vitro leptin secretion by cell cultures, and the proteomic characterization of plasma leptin and its binding-proteins, using RIA, affinity chromatography and other proteomic methods. 3. Identify leptin target tissues by IHC and RRA. The data obtained will help establish hypotheses on physiological function, which will then be tested in comprehensive in vivo studies. If a conserved function is confirmed, the project may explain how key life history transitions such as smoltification and puberty are decided, as the success of such decisions depends to large degree on energy reserves. If alternative physiological functions for leptin in fish are discovered, this is of fundamental importance for understanding evolution and function of endocrine systems in vertebrates, particularly related to the poikilothermic-homeothermic transition. The project is a well-defined, challenging PhD-project, with a broad methodological approach under experiences supervision.
Sweden