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July 1953

THE THREE SUBTYPES OF PITUITARY ADRENOCORTICOTROPINBasic Physiology, Quantitative Human Pharmacology, and Medical Usefulness of ACTH-Corticotropin ("Corticotropin, Crude," "U.S.P. Corticotropin"), ACTX-Corticotropin ("Corticotropin, Purified," "Corticotropin A," "Type I Purified ACTH") and ACTIDE-Corticotropin ("Corticotropin B")

Author Affiliations


From the Rackham Arthritis Research Unit, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Mich. The Rackham Arthritis Research Unit is supported by a grant from the Horace H. Rackham Foundation, School of Graduate Studies, University of Michigan. The present investigations were also assisted by Grants-in-Aid from the National Institutes of Health, United States Public Health Service; from the Michigan Chapter of the Arthritis and Rheumatism Foundation, and from The Armour Laboratories. Generous gifts of corticotropin were received from The Armour Laboratories, The Wilson Laboratories, The Upjohn Company, Eli Lilly & Company, Organon, Inc., Pacific Laboratories, and Victory Packing Company.

AMA Arch Intern Med. 1953;92(1):108-147. doi:10.1001/archinte.1953.00240190120009

CRUDE extracts cannot be medically useful until a satisfactory bioassay method permits their potency to be described in quantitative units which parallel the clinical potency in patients. Bioassay methods for corticotropin were unsatisfactory until the adrenal ascorbic acid depletion method was introduced by Sayers, Sayers, and Woodbury, in 1947.1 Using rats which had been hypophysectomized to remove their source of endogenous corticotropin, these investigators demonstrated a linear relationship between the logarithm of the dosage of intravenously administered corticotropin and the resulting decrease in adrenal ascorbic acid concentration. An acceptable assay permitted standards for corticotropin to be established. The first was the Armour "milligram," later superseded by the International Unit and the U. S. P. unit; all are essentially identical and interchangeable.

Until quite recently, the clinical activity of intramuscularly administered corticotropins appeared to parallel potency determined by the ascorbic acid depletion bioassay, in which the corticotropins are administered intravenously.

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