Related Experiment Video
Updated: Jun 25, 2026

Primary Culture of Rat Adrenocortical Cells and Assays of Steroidogenic Functions
Published on: March 12, 2019
Non-adrenocorticotropin mediated effects of endogenous corticotropin-releasing factor on the adrenocortical activity
1Department of Pharmacology, Medical Faculty, Free University, Amsterdam, The Netherlands.
Abstract:
Diurnal changes in plasma corticosterone concentrations of rats are supposed to be controlled by low amplitude changes in plasma adrenocorticotropin (ACTH) that run in phase with marked changes in adrenal sensitivity to ACTH (1, 2). These sensitivity changes are probably under neuronal control (3), but the mechanisms remain to be elucidated. By the use of a highly specific monoclonal antibody to rat corticotropin-releasing factor (CRF) (4), we studied the role of endogenous CR- in these processes. Blockade of endogenous CRF prevented the evening rise in plasma ACTH and reduced corticosterone levels to less than 10%. The CRF antibody did not affect morning ACTH concentrations but nevertheless reduced morning corticosterone levels by 40% to 60%. In dexamethasone-treated rats, immunoneutralization of endogenous CRF caused a similar reduction in the plasma corticosterone response to exogenous ACTH. We conclude that endogenous CRF plays a physiological role in controlling the adrenal sensitivity to ACTH.
Related Concept Videos
Cushing Syndrome II: Pathophysiology
Cushing Syndrome I: Introduction
Hypothalamic-Pituitary Axis
Hormones of the Adrenal Glands
The adrenal cortex, a powerhouse of hormone synthesis, generates over two dozen corticosteroid hormones. The zona glomerulosa produces mineralocorticoids, exemplified by aldosterone, influencing the electrolyte composition of body fluids. The synthesis of glucocorticoids such as cortisol and corticosterone...
Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Physiological Foundation of Stress
Role of the Sympathetic Nervous System
Adrenaline triggers the...

