Stimulation of in vitro oocyte ovulation by progesterone and homologous pituitary gonadotropic hormone in sturgeons

We showed that the percentage of sturgeon oocytes ovulating in vitro in Ringer solution modified for sturgeons (RMS) considerably depends on the concentration of sodium bicarbonate and the concentration of progesterone. Under optimal conditions (0.5 g/L of sodium bicarbonate and 30 ng/mL of progesterone), it can be higher than 80. Oocytes that matured and ovulated under such conditions are capable of normal development. In the best case, approximately 70% of developing embryos (of the number of ovulated oocytes) reach the stage of hatching (dead-line of observation). This method of producing offspring based on the insemination of oocytes that have matured and ovulated in vitro can be used in work with single females of rare and disappearing sturgeon species.     

Hydration of oocytes in teleost fishes

Data on the hydration of oocytes in teleost fishes during maturation stimulated by gonadotropic or steroid hormones in vivo and in vitro are reviewed. The cause of hydration, its dynamics, and some mechanisms ensuring uptake of water and ions by the oocyte are considered.