The Effect of Adrenocorticotrophic Hormone (Acth) on Cerebral Blood Flow and Metabolism 1

Abstract

While patients receiving adrenocorticotrophic hormone (ACTH) often show an increased sense of well-being and mild euphoria, a small number become psychotic. Electroencephalographic (EEG) changes ( 1 ) have been reported in patients receiving ACTH who become psychotic, but the changes have been inconsistently present. In one instance (2) the EEG changes appeared to be related to a decrease in serum potassium level.These observations led to a study of cerebral blood flow and metabolism in patients receiving ACTH. Concurrent investigation of the EEG (3) and of the clinical and metabolic responses of these subjects will be reported elsewhere (4 All of the patients were studied under similar laboratory conditions in the fasting state. The nitrous oxide method originally described by Kety and Schmidt (5) and modified by Scheinberg and Stead (6) was used. The gas mixture used in the determination consisted of approximately 15% N20, 64% N2, and 21% 0. Arterial blood pressure was measured by the auscultatory method with the arm held at heart level. Mean arterial blood pressures were calculated from these readings by adding one third of the pulse pressure to the diastolic pressure. Blood samples for determination of oxygen and glucose contents were drawn just before and following each cerebral blood flow. The A-V oxygen difference was determined by the method described by Hickam and Frayser (7). The blood glucose content was measured by Nelson's (8) photometric adaptation of the Somogyi method. Cerebral oxygen and glucose utilizations were calculated as previously described (5, 6). RESULTSThe results summarized in Table I show a statistically significant decrease in cerebral blood flow on ACTH treatment from 61 to 50 ml./min./100 gm. brain. After approximately 14 days on therapy no further decrease in cerebral blood flow oc-

The Effect of Acth and Cortisone on Cerebral Blood Flow and Metabolism 1

“…; r 6 A consideration of individual subjects in both the cortisone and ACTH treated series reveals an occasional instance in which a striking reduction in CBF occurred during the administration of the < I X o^drug, with return to its control value after treatment was discontinued. exerts a specific local effect on the cerebral vasculature.…”