Alterations in serum protein levels in patients with Cushing's syndrome before and after successful treatment

Alteration in serum protein concentration is used commonly in clinical prac tice as a nonspecific indicator of underlying disease or to monitor disease activity. Although hypercortisolemia may affect protein metabolism directl y or indirectly, data regarding alterations of levels of serum protein in a large series of patients with Gushing's syndrome (CS) have been lacking. W e have now evaluated, retrospectively, the levels of circulating serum albu min, globulins, total proteins, and the albumin to globulin ratio in 99 pat ients with endogenous CS before, immediately after, and 3, 6, and 12 months following successful treatment. Subjects with concomitant infections or ot her chronic diseases were excluded from the analysis. Although mean serum albumin and total protein levels were within the normal reference ranges, in general, they gradually increased after treatment wit h maximal Values being reached at 12 months after normalization of hypercor tisolemia (P < 0.0001 for both); there were no significant changes in serum globulin levels or in the albumin to globulin ratio. Patients with CS as a whole showed a weak but significant negative correlation between serum alb umin and 0900 h cortisol level (r = -0.303; P = 0.0035). In conclusion, our data suggest that CS is associated with a small but sign ificant reduction in circulating serum protein levels, which are restored f ollowing treatment of hypercortisolemia, although these changes occur withi n the reference range. Thus, extreme alterations in serum total protein or albumin levels in patients with CS should alert physicians to the presence of concomitant pathology, and additional specific investigation should be u ndertaken to elucidate the cause.