Use of embryo culture to study normal development and developmental mechanisms

Mammalian embryo culture techniques have been used to study many aspects of embryonic development. The advantages and limitations of such studies as models for in vivo development are discussed by reference to the following specific examples: development of the paraxial mesoderm, regulation of growth, protein uptake and metabolism, and carbohydrate metabolism. Embryo culture techniques are useful for the study of morphogenesis and growth because the embryo is made accessible for manipulation and observation. Development in vivo and in vitro over equivalent periods can be compared. The limitations of the system have important implications for the interpretation of studies of embryonic metabolism. In vitro metabolic activity can be assessed by assays of the culture media and embryonic tissue at intervals throughout the culture. However, the sensitivity of the metabolic pathways to explantation remains unknown because of the technical difficulties involved in studying embryonic metabolism in vivo.