The unicellular germ cells and gametes of oviparous teleosts lack the osmoregulatory organs present in juveniles and adults, yet during development and particularly at spawning, they face tremendous osmotic challenges when released into the external aquatic environment. Increasing evidence suggests that transmembrane water channels (aquaporins) evolved to play vital adaptive roles that mitigate the osmotic and oxidative stress problems of the developing oocytes , embryos and spermatozoa. In this chapter, we provide a short overview of the diversity of the aquaporin superfamily in teleosts, and summarize the findings that uncovered a highly specific molecular regulation of aquaporins during oogenesis and spermatogenesis. We further review the multiple functions that these channels play during the establishment of egg buoyancy and the activation and detoxification of spermatozoa in the marine environment.
Keywords: Aquaporin; Egg; Hydration; Mitochondria; Motility; Oocyte; Oxidative stress; Sperm.