POMC and myeloid sarcoma: Whereas Gottschalk et al. found a higher activity of the HPA axis in MS fatigue patients, as evidenced by significantly increased adrenocorticotropin (ACTH) concentrations, Heesen et al. reported that HPA-axis feedback-regulation (as determined by the Dex-CRH suppression test) axis activity was not related to fatigue [107, 110].