Tumor-host wasting not explained by adrenal hyperfunction in tumor-bearing animals

Abstract

This study addressed the question of whether hypercorticism in tumor-bearing animals contributes to the wasting of body fat and lean body mass, particularly that of skeletal muscles. For this purpose, hydrocortisone-substituted nongrowing sarcoma-bearing and control C57BL/6J mice were used that were either adrenalectomized or sham-operated prior to experimentation. Adrenalectomy in itself did not alter food intake or body composition in normal animals. Tumor-bearing mice and pair-weighted control animals had elevated urinary excretion of corticosteroids compared with the urinary excretion in freely fed controls. The malignant tumor induced the well-recognized wasting in tumor-bearing animals, irrespective of the presence of the adrenal glands. Therefore, an elevated corticosteroid production did not account for the wasting of body fat, lean body mass, skeletal muscle proteins, or decreased RNA activity in quadriceps muscles from tumor-bearing animals, although such muscles were sensitive to physiologic doses of injected hydrocortisone (20 micrograms/day). Tyrosine aminotransferase (TAT) activity in liver tissue from tumor-bearing animals was higher than that induced by pharmacologic doses of hydrocortisone in normal animals. Physiologic doses of hydrocortisone induced hepatic TAT activity, but pair-weighed control animals with the same degree of hypercorticism as was found in tumor-bearing animals had normal TAT activity in liver tissue. Although hypercorticism is present in tumor-bearing animals, the results demonstrate that cancer cachexia can start and proceed independently of the adrenal glands. Therefore, adrenal hyperfunction is not the proximate cause for the development of experimental cancer cachexia induced by anorexia.