Polysome morphology: evidence for endocrine control during chick embryogenesis.

Surgical removal of the pituitary gland had little apparent effect on the distribution or morphology of skin and feather polysomes in chicken embryos incubated for 12 days. However, polysome patterns obtained from 15-day-old hypophysectomized embryos differed markedly from those of their controls. In addition, a tetrad-shaped polysome, characteristic of the 158S peak of the 12-day-old embryo but not of the 15-day-old control, is still retained in the operated embryo at 15 days. Therefore, it appears that after day 12 of embryogenesis the structure of the four-ribosome polysome from skin and feathers is contingent on a functional hypophysis.