Absence of dorsal-ventral differences in energy metabolism in early embryos of Xenopus laevis.

The establishment of dorsoventral polarity in amphibian development begins prior to the first cleavage with the formation of the gray crescent. It has been suggested that quantitative differences exist in the metabolic activity of dorsal and ventral regions at these stages and that this metabolic activity gradient is involved in the maintenance of dorsoventral polarity. In this study regional metabolism has been examined by the microinjection of various radioactive compounds into dorsal or ventral cells of the four-celled Xenopus laevis embryo. The activities of the Embden-Meyerhof pathway, the pentose shunt, and the Krebs cycle and phosphate metabolism have been measured. No difference was detected in the rate or pattern of metabolism between dorsal and ventral regions, suggesting that metabolic activity gradients do not exist in these pathways during early Xenopus embryogenesis.