Effect of conditioned media on differentiation in mass cultures of chick limb bud cells: I. Morphological effects

Abstract

This paper describes an attempt to study interactions within the developing limb mesoderm tissue by means of tissue culture and conditioned media. Medium was conditioned by very high density cultures (10 000 cells/mm 2) of chondrifying limb bud cells at various stages of this process; confluent cultures of contracting muscle cells; and neural retina cell cultures started at very high density. These conditioned media were fed to very high density cultures of limb bud cells which had not yet begun to chondrify. Chondrogenesis was affected by each conditioned medium in a different and specific manner. Some of these effects were due to factors added during conditioning, others were the result of depletion of unspecified components of the medium. Observations are discussed in terms of product inhibition.