Defined nutrient medium for the in vitro maintenance ofXenopus laevis oocytes

Abstract
A procedure is described for the isolation and culture of large numbers of follicle cell-freeXenopus laevis oocytes in all stages of development. The isolation procedure involves the incubation of pieces of ovary in a calcium-free solution OR2 containing 0.2% collagenase. A defined nutrient medium for the maintenance of the oocytes in vitro is presented. It is shown that this medium, referred to as DNOM, can maintain certain morphological and functional characteristics of oocytes for periods up to 3 weeks.