[The effect of an L-proline analogue, L-azetidine-2-carboxylic acid, on the phenotypic differentiation of the somite mesenchyme of chick embryos].

L-azetidine has been utilized in vivo and in vitro. In vivo, the substance is injected into the yolk sac of young embryos. It inhibits the secretion of the periaxial extracellular material resulting in a lack of several vertebrae. In young vertebral primordia, cultured on L-azetidine, the myotome cells differentiate into myoblasts whereas the sclerotome cells remain undifferentiated. In older primordia, the sclerotome cells give rise to abnormal cartilage but the myotome cells seldom differentiate.