Daily fluctuations in the plasma cortisol level of children with rheumatoid arthritis before and after treatment with tetracosactrin ('Cortrosyn Depot') and corticosteroid hormones.

Daily fluctuations in plasma cortisol levels were studied in three groups of children with rheumatoid arthritis. One group was untreated with hormones, the second treated with a depot preparation of tetracosactrin, and the third group with corticosteroid hormones. The results obtained were compared with the rhythm in normal children. The daily plasma cortisol fluctuations in children with rheumatoid arthritis who did not receive hormonal treatment differed from those of normal children by the presence of two distinct and characteristic cortisol levels: a peak between 8 a.m. and 12 noon and a minimal level between 4 p.m. and midnight (with a gradual rise after 4 p.m.). The curve of the daily cortisol rhythm in children with rheumatoid arthritis after tetracosactrin treatment was characteristic of the curve in normal children. Steroidtreated children with rheumatoid arthritis had virtually unchanged plasma cortisol concentrations throughout the day.