Hypothalamic-pituitary-adrenal function in patients treated with long-term depot tetracosactrin.

Four patients treated with depot tetracosactrin for 10 to 18 months maintained normal hypothalamic-pituitary-adrenal function assessed by the nyctohemeral variation of plasma corticosteroids and by the responses of plasma corticosteroids to insulin-induced hypoglycaemia, lysine-vasopressin, and depot tetracosactrin. The pituitary component of the response was analysed by measuring plasma immunoreactive ACTH levels. Three patients showed a nyctohemeral ACTH rhythm and normal ACTH responses to insulin-induced hypoglycaemia.

Immunoreactive corticotrophin levels in adrenocortical insufficiency.

Plasma concentrations of immunoreactive corticotrophin (ACTH) have been determined in 14 patients with untreated Addison's disease and in 42 patients with secondary adrenocortical insufficiency. Basal morning plasma ACTH levels were markedly raised in those with Addison's disease but were either in the normal range or undetectable in the group with secondary adrenocortical insufficiency. In the group with Addison's disease circulating ACTH values showed a definite nyctohemeral rhythm, a pronounced rise in response to insulin-induced hypoglycaemia, and an immediate fall following the intravenous injection of corticosteroids, with a half-life of between 13.