Two receptor systems for corticosterone (CORT) can be distinguished in rat brain: mineralocorticoidlike or CORT receptors (CR) and glucocorticoid receptors (GR). The microdistribution and extent of occupation of each receptor population by CORT were studied. The CR system is restricted predominantly to the lateral septum and hippocampus. Within the hippocampus, the highest density occurs in the subiculum ± CA1 cell field (144 fmol/mg protein) and the dentate gyrus (104 fmol/mg protein). Affinity of CR for CORT was very high (Kd, ∼0.5 nm). The GR system has a more widespread distribution in the brain. The highest density for GR is in the lateral septum (195 fmol/mg protein), the dentate gyrus (133 fmol/mg protein), the nucleus tractus solitarii and central amygdala. Substantial amounts of GR are present in the paraventricular nucleus and locus coeruleus and low amounts in the raphe area and the subiculum + CA1 cell field. The affinity of GR for CORT (Kd, ∼2.5–5 nm) was 6- to 10-fold lower than that of CR. ...

Two Receptor Systems for Corticosterone in Rat Brain: Microdistribution and Differential Occupation

AS RECENTLY as 1900, tuberculosis, influenza, and pneumonia were the leading causes of death in our country (1). For the most part, however, these infectious diseases, as well as those of poor hygiene or undernutrition, no longer plague us. Instead, we succumb most frequently to heart disease and cancer, diseases of slow degeneration (1). Most of all, unlike so many in the generations before us, we are in a position to age. Regardless of what else occurs, we age, we become more constrained by the discrepancy between what we were and what we have become, and each step becomes harder. The goal in the study of aging is not to halt the process, because we can no more be cured of aging than of birth. The goal, instead, is to slow and soften the sharpest edges of the biological unraveling that constitutes aging. Over the past 5 yr, we have examined some of the sharpest edges of the pathology of aging. We have studied the capacity of aged organisms to respond appropriately to stress and the capacity of stress to...

The Neuroendocrinology of Stress and Aging: The Glucocorticoid Cascade Hypothesis*

Over the past 5 yr, we have examined some of the sharpest edges of the pathology of aging. We have studied the capacity of aged organisms to respond appropriately to stress and the capacity of stre...

The Neuroendocrinology of Stress and Aging: The Glucocorticoid Cascade Hypothesis

The acute effects of corticosteroids on cognition: integration of animal and human model studies

Publisher Summary This chapter discusses the regulation of function in the adrenocortical system. There are three major characteristics that describe most changes in activity of the system: (1) the circadian rhythm in basal activity, (2) stress-induced activation, and (3) corticosteroid feedback regulation. The first two may occur on very different timescales, and it is probably a consequence of the differing temporal demands that the third, corticosteroid feedback inhibition, is exerted by a variety of mechanisms over time. At any time of the day, the adrenocortical system can be activated by application of stressors. These include alteration of the value of a regulated variable or may be invoked by subjecting an animal to sudden disturbances of its environment, for example, noise, flashing lights, handling, strange environment, mild heat or cold. The adrenocortical system may be activated by traumatic stimuli or by psychological stimuli—in man, examinations, or mental arithmetic, or medical school admissions exams; in rats, unexpected decreases in food rewards.

Barbara Sue Stephenson

Papers

Subcutaneous implantation method for chronic glucocorticoid replacement therapy.

Radioimmunoassay of brain tissue and cell nuclear corticosterone