Endocrine Abstracts

Although stressors generally reduce the intake of boring but healthy foods (chow for rats), both acute and repeated restraint stress increase the intake of highly palatable calories (32% sucrose, lard), when they are available. This behavioural effect is mediated by elevated glucocorticoids, and depends on the accompanying increase in circulating insulin concentrations. In the periphery, whereas glucocorticoids mobilize stored calories and greatly increase the rate of gluconeogenesis, insulin counteracts the effects of glucocorticoids, abetting caloric storage. Together, increasing concentrations of both hormones increase adipose storage, at the expense of peripheral protein stores when there is not an overall gain in body weight. Rats that have had ad libitum access to palatable calories have reduced hypothalamo–pituitary–adrenal axis responses to both acute and chronic stressors, and the reduction in hypothalamic corticotropin-releasing factor expression is proportional to the magnitude of fat storage. It seems likely that metabolic feedback signals of plenty reduce the necessity for mobilizing calories from protein to combat threat. Simultaneously, reduced central stress responses ameliorate anxiety from stressors.