Periovulatory female goldfish release three potential pheromones: 17α,20β-Dihydroxyprogesterone, 17α,20β-dihydroxyprogesterone glucuronide, and 17α-hydroxyprogesterone

Our previous studies have shown that 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) produced by preovulatory female goldfish functions both as a hormone promoting oocyte final maturation and as a primer sex pheromone stimulating rapid reproductive endocrine responses in the male. In the present study, the amounts of free and glucuronated 17,20 beta-P as well as free 17 alpha-hydroxyprogesterone (17P) released to the holding water by female goldfish throughout the periovulatory period were determined. Compared to nonovulating female goldfish, ovulating goldfish released very high levels of each of these steroids. This study confirmed that 17,20 beta-P is released to the water by ovulating fish in sufficient amounts to have pheromonal activity and indicated that 17P may also function as a pheromone. Although considerable quantities of 17,20 beta-P glucuronide were also released, its physiological actions are unknown.