The authors tried to obtain information on levels of endogenous plasma cortisol in patients with rheumatoid arthritis and other diffuse connective tissue diseases, in particular systemic lupus erythematosus. Endogenous cortisol was assessed by radioimmunoanalysis at 8 a.m. and 4 p.m. If the sum of the morning and afternoon values reached the level of 280 nmol/l (sum of the lowest still normal values), they considered the daily cortisol secretion still normal. In a group of 30 patients who did not have glucocorticoid therapy the authors found only in one patient a lower daily endogenous cortisol secretion. In 117 patients with a relatively severe course of rheumatoid arthritis where small doses of corticoids (equivalents of 5-10 mg Prednisone) were administered for prolonged periods, a reduced daily secretion of endogenous plasma cortisol was recorded in almost 40%. Repeated examinations made in 13 subjects with rheumatoid arthritis revealed relatively frequent differences in values of endogenous plasma cortisol. In rare instances extremely low plasma levels of endogenous cortisol were found. Similar results as in rheumatoid arthritis, although assessed in a relatively small number of probands, were obtained by the authors also in patients with other diffuse connective tissue diseases, in particular those with systemic lupus erythematosus. Those patients had for prolonged periods roughly double doses of corticoids as compared with patients with rheumatoid arthritis. During repeated examinations the endogenous plasma cortisol levels varied also. The authors are aware that from the assembled results it is so far not possible to draw any definite conclusions and that further investigations are needed which will test the impact of endogenously produced corticoid.

Keywords: Arthritis, Rheumatoid /blood/; Connective Tissue Diseases /blood/; Female; Humans; Hydrocortisone /blood/; Male; Middle Aged