orientation of this volume, particular attention has been given to the regulation of skeletal muscle, adipose tissue, and bone growth. Certain hormones and growth factors have a profound influence on growth regulation and this basic physiological knowledge is being harnessed to maniplilate growth. Thus, considerable emphasis has been given to growth hor­ mone-somatomedinlinsulinlike growth factor regulation of cell and tissue growth. The involvement of peptides coded by protooncogenes and of negative growth regulators, such as transforming growth factor-l3, represents an emerging area of molecular biology wherein basic knowledge offers potential exploitation for growth manipulation. Opportunities also exist for regulation of protein turn­ over, especially from the standpoint of protein degradation. Therefore, a place was reserved for these topics in order to provide relevant basic knowledge.