Immunoreactive Corticotrophin Reserve in Old Age in Man During and After Surgical Stress

Abstract

Attempts have been made to establish whether the immunoreactive corticotrophin (IR-ACTH) reserve was impaired in old age during surgical stress and whether an exhaustion of the IR-ACTH reserve could be traced postoperatively. Recognition of the degenerative changes of the senescent adenohypophysis has made this investigation essential in an effort to analyze factors responsible for the high risk involved in surgery on the aged. In the study 18 young and 14 elderly patients were subjected to elective abdominal or thoracic surgery, and the IR-ACTH response was determined. No significant age-related difference in response to surgery was found. On the sth day after operation an intravenous metyrapone test was carried out, and the IR-ACTH response in plasma determined. In the elderly, the IR-ACTH response to metyrapone was not found to be inferior to that in the young patients. It was concluded that the IR-ACTH reserve was unimpaired during surgery in old age and that exhaustion was not in evidence based on unimpaired IR-ACTH response during repeated stress in the postoperative period. Therefore, decreased acth reserve seems not to be a factor involved in the higher surgical risk in the elderly.