Ultrastructural changes in immature chick oviduct epithelium during avidin induction by actinomycin D.

Avidin induction by actinomycin D may be mediated through cell damage. So the morphology of chick oviduct epithelium was studied 0-24 h after administration of actinomycin D (0.2 mg/kg, i.p.). The avidin content of the oviducts was measured by radioimmunoassay. There were several changes indicating cell damage in both the cytoplasm and nucleus. Marked vesiculation in and around Golgi complexes and the appearance of groups of light vacuoles occurred within 7 h of treatment. Swelling and breakage of mitochondria were found, the perinuclear cleft was enlarged and autophagosomes developed after 12 h. Invagination and swelling of the nucleus occurred during the experimental period. An increase in nuclear pores, polysomes and rough endoplasmic reticulum probably reflected the reparative processes of the cells. Ne secretory granules could be seen. Avidin accumulation began 7 h after actinomycin D, beginning simultaneously with the cell damage and earlier than the marks of regeneration. It is concluded that the avidin induced by actinomycin D is implicated in the severe cell damage caused by the drug.