MC4-RKO mice are resistant to LPS-induced cachexia and illness behavior. LPS reduces food intake for approximately 36 h in WT mice, but not MC4-RKO mice, when expressed as a normalized value (A) or percent basal intake (B). LPS reduces wheel running activity below baseline in WT mice, but not MC4-RKO (C). Normal nocturnal increase in wheel running activity is maintained in MC4-RKO mice despite LPS-challenge. LPS induced growth failure in young WT mice, while young MC4-RKO mice are resistant (D). *, p < 0.05, ** p < 0.01 v. WT control. (Adapted with permission from Marks, D.L.; Ling, N.; and Cone, R.D. Role of the central melanocortin system in cachexia. Cancer Res, 2001. 61: 1432-8. Figure 2.)