Distribution and turnover of testicular hyaluronidase sensitive macromolecules in the primitive streak stage chick blastoderm as revealed by autoradiography.

Primitive streak stage chick blastoderms were cultured for 30 min on a medium containing tritiated glucosamine. Light microscope autoradiography revealed extracellular labeling, and pretreatment of the sections with testicular hyaluronidase suggested the glycosaminoglycan nature of the labeled products. After incorporation of the tritiated precursor, some blastoderms were transferred to a chase medium, and cultured for 30, 90, 210 min. The changes is distribution of the labeled testicular hyaluronidase-sensitive macromolecules during the chase experiment illustrated the ingression of cells in the primitive streak stage chick blastoderm. Grain density differences, resulting from the various chase periods, suggested the renewal of the testicular hyaluronidase-sensitive fraction.