To the editor: I read with interest the paper in the May 1979 issue by Sheeler and Schumacher (1) concerning hyponatremia during adrenocorticotropin (ACTH) infusions. They postulated that ACTH might be contaminated by antiduretic hormone (ADH). Baumann and associates (2) showed that natural ACTH is indeed contaminated by ADH, but that synthetic ACTH does not contain ADH.
In the 48-h ACTH test (3) we now use 50 U of cosyntropin per 24 hours. After several hundred infusions we have not encountered hyponatremia.