ACTH LEVELS IN PLASMA IN PREOPERATIVE AND SURGICALLY STRESSED PATIENTS*

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Abstract
Ten patients, undergoing elective surgery at the Los Angeles County General Hospital, had preoperative and postoperative blood samples drawn for determination of plasma. Plasma 17-hydroxy-corticosteroids were determined on the same samples in two of these patients. The plasma ACTH was determined by a slight modification of the Lipscomb-Nelson assay, which involves estimation of cortico-sterone in the adrenal venous blood of rats 2 hours after hypophysectomy. The assay as used in this study is described. All of the plasma ACTH levels in the preoperative samples were within the "normal" range for this laboratory. Most of the samples studied 0.5 hour after the operation had elevated levels, which returned toward normal by 4 hours, and all were normal by 24 hours postoperatively. As a group, the ACTH levels in the preoperative and 24-hour postoperative plasma samples were indistinguishable from each other and equivalent to approximately 0.6 mu per 100 ml plasma. The previous evidence for plasma corticoid elevation during surgery, together with suggested mechanisms, is presented and discussed. An increase in plasma ACTH occurred coincident with an elevation in plasma corticosteroids which under these circumstances failed to produce a suppression of plasma ACTH.