Effects of cytochalasin H on chick embryo explants cultured in vitro.

Effects of the mould metabolite, cytochalasin H (CH) were studied in chick embryos explanted at stages 4, 5 and 8 and cultured in vitro. Morphological and histological observations revealed that the major effects of CH are inhibition of primary morphogenesis of heart and disaggregation of cells. Inhibition of neural tube closure, microcephaly and shortening of body axis was also noted. The effects were found to be dose- and stage-dependent. Histochemical studies demonstrated that CH brings about a reduction in the contents of glycoproteins and non-sulfated glycosaminoglycans important in cell adhesion. Effects of CH appeared due to its interference primarily with cell adhesion and secondarily with morphogenetic movements.