Actinomycin D: inhibition of phospholipid synthesis in chick embryo cells.

When chick embryo fibroblasts are exposed to actinomycin D for 30 minutes to 3 hours, there is progressive inhibition of phospholipid synthesis, so that by 3 hours the inhibition is 40 percent. All phospholipids are affected. Since this inhibition is twice as great as the inhibition of protein synthesis, some effects of actinomycin D previously ascribed to decreased protein synthesis must be reevaluated.