Decreased response of plasma cortisol to intravenous metyrapone in ocular hypertension and primary open-angle glaucoma.
OBJECTIVE
To determine if there is a difference in response to metyrapone, which blocks the conversion of 11-deoxycortisol to cortisol in the adrenal gland between normals and ocular hypertensives (OH) plus primary open-angle glaucomas (POAG) without pigmented angles.


METHODS
Intravenous metyrapone was given to 20 normals and 15 ocular hypertensives plus primary open-angle glaucomas without pigmented angles. Blood samples were obtained at 4, 6, and 8 hours after administration of intravenous metyrapone for analyses of 11-deoxycortisol and cortisol.


RESULTS
The ocular hypertensives plus primary open-angle glaucoma group showed significantly lower cortisol values compared with the normal group at 6 hours (P = 0.002) but not at 4 or 8 hours. There were no significant differences between the two groups for 11-deoxycortisol values at 4, 6, or 8 hours. The percent decrease of plasma cortisol from baseline was significantly greater for the ocular hypertensives plus open-angle glaucoma group compared with the normals at 4 hours (P = 0.010) and 6 hours (P = 0.0004). Significant negative correlations were observed for the total group of subjects between levels of plasma cortisol at 6 hours and intraocular pressure, worse eye (P = 0.029), percent area of cupping, worse eye (P = 0.045), pallor, worse eye (P = 0.001), and visual field loss, worse eye (P = 0.048), so that the less the plasma cortisol, the greater the abnormality of the glaucomatous parameters. Multivariate analyses with the 6-hour plasma cortisol level as the dependent variable showed that the only significant (P = 0.0004) independent variable was the percent area of pallor, worse eye, associated with a smaller level of plasma cortisol at 6 hours. Similarly, the multiple regression models using the percent change from baseline of the 6-hour plasma cortisol value showed a significant association of larger percent decreases of plasma cortisol in the ocular hypertensives plus open-angle glaucoma compared with the normals.


CONCLUSIONS
The ocular hypertensives plus primary open-angle glaucoma subjects show greater adrenal inhibition to metyrapone in the synthesis of cortisol from 11-deoxycortisol compared with normals. This observation suggests an adrenal abnormality in the ocular hypertensive plus primary open-angle glaucoma subjects.
Schwartz
Bernard
B
Tufts University School of Medicine, Boston, Massachusetts, USA. glaucomares@mva.net
Wysocki
Alice
A
Qi
Youlin
Y
D000368:Aged; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000097:blood* / Q000503:physiopathology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007262:Infusions, Intravenous; D007429:Intraocular Pressure; D008297:Male; D008797:Metyrapone / Q000008:administration & dosage*; D009798:Ocular Hypertension / Q000097:blood / Q000503:physiopathology; D010913:Pituitary-Adrenal System / Q000502:physiology; D011863:Radioimmunoassay
D004791:Enzyme Inhibitors; D006854:Hydrocortisone; D008797:Metyrapone