Fat Metabolism in Experimental Obesities

VII. Lipogenesis and Cholesterologenesis in Mice With Adrenocorticotropic Tumors

¹ From the Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts

In vivo incorporation of acetate-1-C¹⁴ into fatty acids and cholesterol by carcass and liver was determined 30 minutes after injection of the labeled acetate in mice grafted with adrenocorticotropin-secreting tumors. Serum cholesterol levels were also determined. Lipogenesis is elevated under fed and fasted conditions in mice bearing adrenocorticotropin-secreting tumors as compared with normal controls or tumor-bearing adrenalectomized mice. Cholesterologenesis was not significantly different in fed tumor-bearing and control mice. When fasted, however, the tumor-bearing mice exhibited greater incorporation of C¹⁴ than that of their controls. Fasting did not decrease cholesterologenesis in the former group. Serum cholesterol levels of the adrenocorticotropic mice were found to be twice as high as those of controls. In addition, the amounts of carcass and liver fatty acids were three times as great for the ACTH mice as compared with controls, although their body weights did not differ significantly. Carcass and liver cholesterol content of adrenocorticotropic mice was also elevated. The results of this experiment indicate that mice bearing adrenocorticotropin-secreting tumors exhibit a ‘metabolic’ type of obesity.