FROM WHOLE-BODY TO MOLECULE - AN INTEGRATED APPROACH TO THE REGULATION OF METABOLISM AND GROWTH

This paper considers the use of whole-body calorimetry in a wide conte xt, as one of a range of techniques available for advancing our knowle dge of the regulation of energy metabolism and growth. This integrated approach should lead to a greater depth of understanding by investiga ting the mechanisms by which responses of the whole animal depend on e vents at the tissue, cellular and molecular levels. Two critical stage s of mammalian development, the perinatal and early postnatal periods, are discussed. Particular attention is paid to skeletal muscle and th e extent to which myofibre differentiation and hypertrophy, and hence muscle function and energetic efficiency, can be modified by nutrition and the thermal environment. In view of the crucial roles of thyroid hormones, growth hormone and insulin-like growth factor-I in regulatio n of metabolism and growth, the role of the endocrine system is also c onsidered. These studies have important implications for survival and optimal health of humans and other animals.