Linking mechanistic and behavioral responses to sublethal esfenvalerate exposure in the endangered delta smelt; Hypomesus transpacificus (Fam. Osmeridae)

Connon, Richard E; Geist, Juergen; Pfeiff, Janice; Loguinov, Alexander V; D'Abronzo, Leandro S; Wintz, Henri; Vulpe, Christopher D; Werner, Inge

vii Osmotic Stress A hyperosmotic glycine rich protein was identified with the microarrays as significantly downregulated by exposure to 0.0625 μg.L -1 esfenvalerate in 52-d old larvae. Osmoregulation is physiologically controlled by chemical messages from the endocrine system, along with cell signalling and nerve transmission [81] . Pyrethroids have been suggested to induce osmotic imbalances in common carp larvae [82] which are linked to effects on ATPase activity responsible for maintaining the Sodium transmembrane electrochemical gradient [83] . Larval fish are under direct exposure to osmotic stress as their endocrine system is not fully developed [84] . Parvalbumin and choriogenin expression have indicated possible effects on the endocrine system, thus expression of this hyperosmotic glycine rich protein may be directly caused by conditions affecting endocrine regulation.