A method for the production of pigmentless eggs in Xenopus laevis

Pigmentless oocytes may be obtained from adult Xenopus laevis females by a combination of repeated induced ovulations with human chorionic gonadotrophin (HCG) and the continuous administration of the antimelanogenic compound phenylthiourea (PTU). Pigmentless eggs obtained in this manner are apparently normal since they may be fertilized and subsequently develop into normal, but pigmentless, embryos and tadpoles. Cessation of the PTU and HCG treatments results in normal pigmentation of immature oocytes; however, those oocytes which are more nearly mature become pigmented to a lesser degree. Those oocytes which are mature at the time treatment is stopped remain pigmentless.