L'ONTOGENESE INTESTINALE DES AMPHIBIENS: IMPORTANCE DE LA METAMORPHOSE. ETUDE COMPARATIVE AVEC LES AUTRES VERTEBRES.

Metamorphosis is a characteristic event of Anuran Amphibian post-embryonic development It is related to a change in environment and in feeding behaviour. Among many transformations, intestine undergoes remarkable modifications : it shortens, loses its coiled shape and a folded secondary epithelium is put in place of larval epithelial cell lining. In parallel with epithelium substitution, at cellular level, quantitative and qualitative changes in genes expression are noted, triggered by thyroid hormones. Microvillar proteins are concerned as membrane-bound enzymes or structural cytoskeleton components (for example, villin). Such a late intestinal maturation is also observed in other Vertebrates, especially during Agnathans metamorphosis, Birds hatching or Mammalians birth and weaning