Neural Control of Adrenocortical Function

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

While hormonal responses to stress are well known, the mechanisms of neural control in regulating such responses are not well understood. An animal under stress shows increased blood levels of adrenocorticotropic hormone, ACTH. ACTH in turn stimulates steroidogenesis in the tissue of the adrenal cortex, which generates and releases corticosterone, a steroid glucocorticoid compound. However, there has been a long-standing problem that the patterns of ACTH levels in the blood often do not match changes in circulating glucocorticoid levels. Recent discoveries suggest that this steroidogenic response of the adrenal cortex also is regulated by activity of the splanchnic nerve coming from the spinal cord. This renewal project combines physiological and molecular approaches to identify the mechanisms involved. Experiments will test how blocking neural activity changes the expression of biochemical enzymes and receptor proteins that are part of the steroidogenic pathway, how neuronal stimulation might modulate changes by regulating adrenal blood flow, and which nerve fiber types (preganglionic sympathetic or primary afferent fibers) mediate the observed changes in steroidogenesis. Results will define a novel mechanism for regulation of hormone activity in response to stress, which will have an impact on understanding neural control systems in general, and can be important for management of stress in contexts such as agriculture as well as human behavior. The project also involves student training in state-of-the-art technology in a very productive laboratory.