Initial studies of the effect of surgical manipulation (i.e. parathyroid and thyroid surgery) on the effect of hormone (ACTH, B endorphin, cortisol, tissue CRH, vasopressin, oxytocin, catecholamine, angiotensin II, cyclic AMP) levels did not show significant alteration. Instead, anesthesia changes (with induction and reversal) had the most dramatic effects. In this study, the degree of surgical stress has been increased (i.e. laparotomy), the anesthetic has been kept relatively constant and the hormone levels have been measured. A significant change is expected.
