To determine whether daytime or nighttime cortisol secretion is aberrant in
patients with multiple system atrophy (MSA), the plasma cortisol concentra
tions in 20 patients with MSA were measured at 4-hr intervals for one day.
Ten age-matched healthy individuals and 20 patients with cerebral infarctio
n but without hypothalamic lesions were used as controls. The results showe
d that morning (8 A.M.) cortisol concentrations in patients with MSA were s
ignificantly lower than those in the control subjects. This phenomenon is h
ighly associated with dysfunction in the autonomic nervous system in MSA.