Diurnal variation of prednisolone binding to serum corticosteroid-binding globulin in man

摘要: Serum corticosteroid-binding globulin (CBG, transcortin) binding capacity for prednisolone and cortisol, levels of the circulating cortisol were evaluated in healthy adult subjects patients under long-term treatment with prednisone. Blood samples drawn at 4-hr intervals throughout least 24 hr; prednisone administration was discontinued hr before starting examination. Circadian fluctuations CBG-binding occurred subjects: maximum 12 midnight minimum 8 a.m. The diurnal pattern prednisolone-binding characterized by phase shifts approximately compared those serum cortisol-binding capacity, respectively. There no variations prednisolone- prednisone-treated patients. Moreover, both capacities, expressed as micrograms bound steroid/100 ml, significantly reduced respect to normal control subjects. Cyclic may represent an additional factor accounting temporal differences action synthetic corticoids which are transport protein. Synthetic derivatives when chronically administered interfere not only adrenal secretion but also glucocorticoids.