Development of a culture medium for growing xenopus laevis oocytes

A defined medium for growing defolliculated Xenopus laevis oocytes was developed by monitoring vitellogenin incorporation. Optimum conditions were achieved by use of 50% Liebovitz L‐15 medium supplemented with 1 mM L‐glutamine, 15 mM Hepes, 5 mg/ml vitellogenin, and 1 μg/ml insulin (final pH = 7.8). Stage IV/V oocytes remained morphologically normal in this medium for at least two weeks and grew at an average rate of 0.25 mm 3 per week. This is the first time defolliculated Xenopus laevis oocytes have been grown in vitro.