AGXT and obesity due to melanocortin 4 receptor deficiency: For instance, myriocin, inhibitor of serine palmitoyl transferase (SPT); L-cycloserine and fumonisin B1, inhibitors of de novo ceramide synthesis by desaturase 1 (DES1); and L-alpha-phosphatidyl-D-myo-inositol-3,5-bisphosphate, inhibitor of acid sphingomyelinase (ASMase), represent compounds known to us to be effective in different experimental models of obesity, but, unfortunately, are still not available for clinical use [33,34].