METHODS FOR ENDOCRINE STUDIES OF A WILD-S PECIES, THE EEL

Studying hormonal regulations which are responsible for the control of main functions such as development, growth and reproduction, is of sp ecial interest in the eel, due to the peculiar biological cycle of thi s fish. Such a study has both fondamental aims (knowledge of eel biolo gy, use of the eel as a model, ecophysiology, evolution) and applied o nes (characteristics of eel populations, control of eel biological cyc le). However, the complexity and the present lack of data on the eel b iological cycle provide special difficulties (lack of natural referenc es concerning the physiological characteristics and the environmental conditions of the last steps of the cycle), in addition to those encou ntered with the study of a peculiar species (need for development of s pecific research tools), a wild species (physiological and genetical h eterogeneity of the animals) and an endangered species (limitation of the number of experimental animals). The use of various investigation methods, including development of molecular tools (hormonal purificati on, antibodies production, immunological assays, cloning and probe obt ention), in vitro (cell culture, organ incubation or perifusion) and i n vivo (gland ablation, hormonal treatments, blood samples...) studies as well as field experiments, leads to a whole and integrative approa ch of eel endocrinology.