Exploration biologique de la fonction corticotrope

Cortisol is the major glucocorticoid hormone synthesized by the adrenal cortex in response to adrenocorticotropic hormone (ACTH) which is secreted by the pituitary gland. Pituitary ACTH is stimulated by hypothalamic peptides: corticotropin-releasing factor (CRF) and vasopressine. Cortisol is involved in a negative feedback loop with hypothalamic and pituitary hormones synthesis and secretion. Production of cortisol is dependant of the hypothalamopituitary-adrenal cortex axis (HPA) functioning, and of the presence of enzymes responsible of different synthesis pathways of steroids hormones. Biological exploration of adrenocortical function is assessed by measurement of basal cortisol and ACTH levels, and by stimulation or suppression tests allowing informations about dysfunction of any organ in the HPA axis resulting in abnormal secretion of cortisol: overproduction in Cushing's syndrom, or primary adrenal insufficiency and secondary or hypothamo-pituitary insufficiency.