Effect of dexamethasone on the diurnal rhythm of plasma aldosterone in patients with congestive heart failure.
Diurnal rhythm studies were performed on 11 patients with congestive heart failure. Blood samples were taken for the determination of aldosterone, cortisol and plasma renin activity every 4 hours from 12:00 a.m. to 12:00 a.m. the following day. Following this control study, a second diurnal rhythm study was conducted under dexamethasone treatment (0.5 mg of dexamethasone every 4 hours for 48 hours). In the control study, aldosterone and cortisol fluctuated showing a diurnal rhythm with the lowest value in the evening and the highest value in the morning. Plasma renin activity rhythm was indistinct. Fluctuations in plasma renin activity were not parallel with aldosterone. Dexamethasone treatment suppressed cortisol to less than 1 microgram/100 ml. Aldosterone values decreased significantly in the morning (p less than 0.01); this was accompanied by the abolishment of aldosterone rhythm. Plasma renin activity rhythm remained indistinct following administration of dexamethasone. These results suggest that adrenocorticotrophic hormone plays an important role in the control of aldosterone diurnal rhythm in patients with congestive heart failure.
D000293:Adolescent; D000328:Adult; D000450:Aldosterone / Q000097:blood*; D002940:Circadian Rhythm; D003907:Dexamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000188:drug therapy; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008875:Middle Aged; D012083:Renin / Q000097:blood
D000450:Aldosterone; D003907:Dexamethasone; D012083:Renin; D006854:Hydrocortisone