Vulto A, et al. - In primary adrenal insufficiency and secondary adrenal insufficiency patients, researchers assessed the precursors of endogenous corticosteroid production. This ancillary analysis of two different studies involved 20 patients with primary adrenal insufficiency and matched controls and 19 patients with secondary adrenal insufficiency. In a substantial proportion of patients with both primary and secondary adrenal insufficiency, adrenal corticosteroid production will probably continue during treatment. This synthesis appears to be sensitive to a dose of hydrocortisone in patients with secondary adrenal insufficiency. The residual concentrations of corticosteroids, however, were quantitatively low, so its clinical value has not been determined.