Simultaneous measurement of plasma 18-oxocortisol and 18-hydroxycortisol levels in normal man.
Plasma 18-oxocortisol (18-oxoF) and 18-hydroxycortisol (18-OH-F) were measured in 47 healthy subjects. Plasma 18-oxoF and 18-OH-F in the early morning were 0.827 +/- 0.04 nmol/l and 3.29 +/- 0.175 nmol/l, respectively. The plasma levels of both steroids correlated with each other and with cortisol, but not with aldosterone. Postural stimulation with or without furosemide administration increased 18-oxoF, 18-OH-F, aldosterone and plasma renin activity (PRA). Two hours after 2 mg of oral dexamethasone administration or after an overnight 2 mg of dexamethasone suppression cortisol, 18-oxoF and 18-OH-F decreased. Cortisol, aldosterone, 18-oxo-F and 18-OH-F increased after the intravenous administration of 250 micrograms of 1-24 ACTH. Changes in plasma 18-oxo-F and 18-OH-F levels correlated with PRA change during the posture studies and correlated with the change of ACTH during the dexamethasone studies. The ratios of post-/pre-test values of the postural stimulation and dexamethasone suppression in 18-oxoF and 18-OH-F were lower than that of aldosterone. Plasma 18-oxoF and 18-OH-F are more dependent on ACTH than on the renin-angiotensin system. The ratio of 18-OH-F/18-oxoF, which is between 4 and 5, remains constant during the various stimulation or suppression maneuvers.
Yamakita
N
N
Department of Internal Medicine, Matsunami General Hospital, Gifu-Prefecture, Japan.
Gomez-Sanchez
C E
CE
Mune
T
T
Morita
H
H
Yoshida
H
H
Miyazaki
S
S
Yasuda
K
K
D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000502:physiology; D000328:Adult; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000097:blood; D008297:Male; D011187:Posture; D012016:Reference Values
C038135:18-oxocortisol; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; C033689:18-hydroxycortisol; D006854:Hydrocortisone