an attempt to rationalize these terminological and conceptual difficulties we have considered the origins of mammalian heat production from two different points of view. The scheme depicted in Fig. 1. 1 illustrates the fate of energy in the body as seen by the nutritionist. After allowing for losses of energy in faeces and urine, the metabolizable energy obtained from food is utilized for main taining and increasing body energy content (maintenance, external work, growth and production). The transformation of metabolizable energy into these forms of net energy also involves inevitable energy losses in the form of heat - thermic energy. Similarly, maintaining homeothermy in cold en vironments involves shivering and non-shivering thermogenesis (NST) and the energy costs of assimilating nutrients and retaining net energy results in obligatory heat losses due to diet-induced thermogenesis (DIT). This obligatory DIT is mainly due to the energy cost of protein and fat synthesis but, in addition to this, there is an adaptive component of DIT that helps maintain body energy content (i. e. body weight) by dissipating the metabolizable energy consumed in excess of the requirements for maintenance, growth and production. In Fig. 1. 2, we have converted this nutritionist's scheme (A) into one that A B r-------. . . , I I Production, Growth I I External work I I I I Essential energy expenditure NET BASAL Obligatory 1 I ENERGY Maintenance HEAT heat I FASTING at (BMR) productlpn for t ROC thermoneutrallty homeothermia r.
|Edition description:||Softcover reprint of the original 1st ed. 1983|
|Product dimensions:||6.10(w) x 9.25(h) x 0.03(d)|
Table of Contents1 Mammalian Thermogenesis: An Introduction.- 2 Cellular Mechanisms of Heat Dissipation.- 2.1 Introduction.- 2.2 The thermodynamics of heat dissipation.- 2.3 Extra-mitochondrial ATP-hydrolysing mechanisms: general considerations.- 2.4 The status of ATP-hydrolysing mechanisms in brown fat.- 2.5 Mitochondrial dissipatory mechanisms: general considerations.- 2.6 The proton short-circuit of brown-fat mitochondria.- 2.7 The molecular basis for the adaptive cold- and diet-induced increase in brown-fat thermogenic capacity.- 2.8 The acute regulation of the proton short-circuit in brown-fat mitochondria.- 2.9 Conclusions.- References.- 3 Brown Fat: An Energy Dissipating Tissue.- 3.1 Introduction.- 3.2 The survival value of an energy dissipator.- 3.3 Anatomy.- 3.4 The capacity for heat production.- 3.5 Evidence for a concerted regulation between substrate supply and respiration rate.- 3.6 Tissue blood flow.- 3.7 The adaptive response to cold exposure.- 3.8 The acute thermogenic response.- 3.9 Alpha- and beta-adrenergic mediated membrane potential changes and metabolism.- 3.10 Sodium pump and thermogenesis.- 3.11 Control of brown-fat thermogenesis.- References.- 4 Autonomic Regulation of Thermogenesis.- 4.1 Introduction.- 4.2 Cold exposure.- 4.3 Diet.- 4.4 Summary and conclusions.- References.- 5 Thyroid Hormones and Thermogenesis.- 5.1 Introduction.- 5.2 Role of thyroid hormones in thermogenesis.- 5.3 Summary.- References.- 6 Energetics of Maintenance and Growth.- 6.1 Measurement of energy exchange.- 6.2 The energy cost of maintenance and fattening.- 6.3 Food intake and heat production.- 6.4 Eating and rumination.- 6.5 Efficiency of utilization of absorbed nutrients.- 6.6 Regulatory dietary-induced thermogenesis.- 6.7 Body size and heat production.- 6.8 The energetics of growth.- 6.9 Conclusions.- References.- 7 Diet-Induced Thermogenesis.- 7.1 Introduction.- 7.2 Force-feeding and diet-induced thermogenesis.- 7.3 Voluntary hyperphagia and diet-induced thermogenesis.- 7.4 Mechanism of diet-induced thermogenesis.- 7.5 Other factors affecting diet-induced thermogenesis.- 7.6 Reduced thermogenesis.- 7.7 Summary.- References.- 8 Thermogenesis and Obesity.- 8.1 Introduction.- 8.2 Energy balance in genetically obese rodents.- 8.3 Mechanisms of heat production.- 8.4 Thermogenesis in man.- 8.5 Concluding comments.- References.- 9 Hypermetabolism in Trauma.- 9.1 Introduction.- 9.2 Afferent mediators of metabolic alterations.- 9.3 Neuroendocrine responses.- 9.4 Metabolic responses.- 9.5 Cardiovascular responses.- 9.6 Thermoregulatory response.- 9.7 Treatment.- 9.8 Summary.- References.- 10 Thermogenesis and Fever.- 10.1 Temperature regulation as a reflex.- 10.2 The biology of fever.- 10.3 The biology of malignant hyperthermia.- References.- 11 Pharmacology of Thermogenesis.- 11.1 Introduction.- 11.2 Central control of thermogenesis.- 11.3 Neural control of shivering and non-shivering thermogenesis.- 11.4 Receptors mediating thermogenic responses in brown adipose tissue.- 11.5 Intracellular mediators of the acute, subacute and chronic effects of sympathetic stimulation.- 11.6 Impact of various pharmacological agents on thermogenesis.- 11.7 Hormonal control of thermogenesis.- 11.8 A rationale for selecting thermogenic agents.- References.