Living organisms have regular patterns and routines that involve obtaining food and carrying out life history stages such as breeding, migrating, molting, and hibernating. The acquisition, utilization, and storage of energy reserves (and other resources) are critical to lifetime reproductive success. There are also responses to predictable changes, e.g., seasonal, and unpredictable challenges, ...

Homeostasis stabilizes critical biological variables within appropriate limits via corrective regulatory effector responses that adequately counter disturbing effects. Identifying individual effects and responses, and distinguishing their individual influences on a regulated state, is challenging. Studying effector responses can reveal regulatory phenomena that depart from homeostasis into the ...

The adaptive responses of the body that maintain homeostasis in response to stressors can be called "allostasis", meaning "achieving stability through change". Mediators produced by the immune system, autonomic nervous system (ANS) and hypothalamo-pituitary-adrenal(HPA) axis produce allostasis. The brain also shows allostasis, involving the activation of nerve cell activity and the release of n...

The term allostasis, which is defined as stability through change, has been invoked repeatedly by developmental psychopathologists to describe long-lasting and in some cases permanent functional alterations in limbic-hypothalamic-pituitary-adrenal axis responding following recurrent and/or prolonged exposure to stress. Increasingly, allostatic load models have also been invoked to describe psyc...

PDC (pyruvate dehydrogenase complex) catalyses the oxidative decarboxylation of pyruvate, linking glycolysis to the tricarboxylic acid cycle. Regulation of PDC determines and reflects substrate preference and is critical to the 'glucose-fatty acid cycle', a concept of reciprocal regulation of lipid and glucose oxidation to maintain glucose homoeostasis developed by Philip Randle. Mammalian PDC ...

The hypothalamus-pituitary-thyroid feedback control is a dynamic, adaptive system. In situations of illness and deprivation of energy representing type 1 allostasis, the stress response operates to alter both its set point and peripheral transfer parameters. In contrast, type 2 allostatic load, typically effective in psychosocial stress, pregnancy, metabolic syndrome, and adaptation to cold, pr...

The brain is constantly adapting to a changing environment. It detects environmental stimuli, integrates that information with internal states, and engages appropriate behavioral and physiological responses. This process of stability through change is termed "allostasis", and serves as a mechanism by which an organism can adapt to a changing environment to function optimally, and ultimately ens...