The Physiology of the Xenopus laevis Ovary

Xenopus laevis has been used for many decades to study oocyte development and maturation. The Xenopus oocytes' large size, relative abundance, and clearly defined progression of physical characteristics from oogonia to eggs make them ideal for studying oogenesis. In addition, the ability of steroids to trigger Xenopus oocyte maturation in vitro has resulted in their extensive use for the study of the complexities of meiosis. Interestingly, steroid-induced maturation of Xenopus oocytes occurs completely independent of transcription; thus, this process serves as one of the few biologically relevant models of nongenomic steroid-mediated signaling. Finally, Xenopus oocytes appear to play a critical role in ovarian steroidogenesis, suggesting that the Xenopus ovary may serve as a novel system for studying steroidogenesis. Evidence indicates that many of the features defining Xenopus laevis oogenesis and maturation might also be occurring in mammals, further emphasizing the strength and relevance of Xenopus laevis as a model for ovarian development and function.