Abstract
Oocytes of the orange-red type female of the medaka, Oryzias latipes were isolated 2-3 hours before the germinal vesicle breakdown.They were cultured in vitro in various media and germinal vesicle breakdown, ovulation, and development upon insemination were observed.The medium suitable for oocytes to acquire the developmental capacity was selected from various media.There appeared to be little effect of glucose (0.5-2 mg/ml) or sodium pyruvate (0.1-2 mg/ml) in the external medium on the oocyte maturation. Oocytes could mature in the presence of bovine serum albumin in Yamamoto's salt solution, although they failed to mature in Yamamoto's salt soultion without bovine serum albumin. Bovine serum albumin was dispensable for the medium which was finally selected for oocyte culture.Composition of salts in the most suitable medium was as follows: NaCl 6.5 mg/ml, KC1 0.4 mg/ml, CaCl2·2H2O 0.15 mg/ml, and adjusted by N/10 NaHCO3 to pH 7.3.
