ACE and obesity due to melanocortin 4 receptor deficiency: (Ejerblad et al., 2006) Another possible reason for the lack of arterial pressure reduction to an ACE inhibitor in the SSLepRmutant strain is the impact of other obesity-related mediators (i.e., endothelin, 20-HETE, and catecholamines) that could contribute to the maintenance of arterial pressure.