[Diurnal rhythm of cortisol and aldosterone plasma levels in patients with chronic renal insufficiency].

UNLABELLED

In patients with chronic renal failure (CRF) disturbances in cortical adrenal endocrine function were described previously. An increased plasma aldosterone level was documented in several studies [1-4]. The aim of this study was to investigate diurnal rhythms of plasma cortisol and aldosterone in CRF patients. In addition, in 3 patients on maintenance haemodialysis, the effect of dialysis procedure upon the plasma level of these hormones was studied. Ten patients with CRF of different etiologies, mean age 41.2 years, serum creatinine from 166-1336 mumol/L, creatinine clearance 4.2-29.2 ml/min, participated in the study. Blood samples were taken in the recumbent position at 6 am and at 6 h intervals thereafter for 24 h. Another group was made of 3 patients on maintenance haemodialysis for a mean 4.2 years. The effect of dialysis upon plasma cortisol and aldosterone levels was studied in the morning (7-11 h) and afternoon hours (14-18 h), with blood samples taken at one hour intervals. Patients were dialysed on cuprophan and polyacrilonitrile membranes. Plasma cortisol and aldosterone levels were determined using commercial RIA kits from Sorin Biomedica, Italy. The results obtained show that in 8 out of 10 patients with CRF in the predialysis period diurnal rhythm of cortisol was preserved. Investigation of the plasma aldosterone, with a 6 h sampling, however, shows in most of the patients studied no changes indicating a preserved diurnal rhythm. Investigation of the effect of haemodialysis treatment performed for 4 h on cuprophane as well as on PAN membrane, upon the plasma cortisol level has shown in morning hours the unchanged plasma cortisol level, compared to the same patients during the control study. Haemodialysis in the afternoon hours has produced, a small decrease of plasma cortisol during the first two hours, followed by an increase to the predialysis values. Plasma aldosterone levels during the morning and afternoon haemodialysis have shown variations similar to that observed in the same patients during the control study.

CONCLUSIONS

This study has shown a preserved circadian rhythm of cortisol in kidney patients with CRF. A clear diurnal rhythm of aldosterone in these patients cannot be established. Investigation of the effect of haemodialysis procedure, performed on cuprophan and PAN, a more permeable membrane, upon the plasma levels of cortisol and aldosterone, has shown variations similar to that observed during the control study.