Abstract
The Metopirone test has been compared to 2 other measures of pituitary ACTH secretion, the insulin tolerance test and the water-loading test, in a variety of patient groups. The results confirm the impression that the Metopirone test is the most sensitive measure now available for assessing pituitary ACTH secretory capacity. Discrepancies between the Metopirone and insulin tolerance tests were noted, indicating that the Metopirone test should be considered a measure of only one aspect of pituitary ACTH secretory capacity, and not necessarily a measure of total reserve.