Different patterns of energy metabolism in the rat and mouse zygate

The development of rat zygotes in vitro to the two-cell stage occurred if lactate, phosphoenolpyruvate (PEP), pyruvate or oxaloacetate were present in the media. When rat and mouse zygotes were cultured in the same droplet of medium containing lactate or PEP, mouse zygotes did not develop to the two-cell stage but the rat zygotes cleaved.