Differential Protein Distribution Related to Dorsoventral Polarity in Pleurodeles waltl Cleaving Egg: (Pleurodeles waltl/dorsoventral polarity/regional protein pattern).

The molecular basis for the initial specification of dorsoventral polarity in the Amphibian egg prior to the mid-blastula transition still remains an open question. Regional differences in the protein pattern of Pleurodeles egg were investigated during early cleavage (8- and 512-cell stages, prior to the mid-blastula transition). Animal-dorsal, animal-ventral, vegetal-dorsal and vegetal-ventral quarters were separated and proteins were analyzed by 2D-electrophoresis.

Effects of thyroxine on the ontogeny of the vitellogenic response in Pleurodeles waltli of both sexes.

In the newt, Pleurodeles waltli, vitellogenin synthesis can be induced by oestrogen prior to metamorphosis and well before vitellogenin synthesis is normally observed in females. Vitellogenin indicubility has been shown to occur during normal development at stage 53 in both sexes. Immersion of young larvae in thyroxine at concentrations that did not result in early morphological metamorphosis led to a precocious acquisition of liver responsiveness to oestrogen.