The level and circadian rhythm of plasma free 11-hydroxycorticoids in patients with localized intracranial processes, especially of the sellar region.

Abstract

The circadian plasma cortisol pattern was studied in 35 cases with pituitary tumours, in 49 cases where a pituitary tumour, had been removed, in 20 cases with optic atrophy not caused by tumour and in 65 cases with other localized intracranial processes. Nineteen persons served as controls. In the control group the mean plasma cortisol level was 14.9 (SD = 3.4) μg/100 ml plasma and the difference between the highest measured morning value and the lowest measured evening value was 16.6 (SD = 5.1) μg/100 ml plasma. The diurnal rhythm was normal in patients with intrasellar tumours and in those with optic atrophy. In patients with a suprasellar extension of the pituitary tumour and in patients from whom a pituitary tumour had been removed the plasma cortisol rhythm and/or level was pathological in 23 out of 58 cases. In these cases the mean values of the plasma cortisol levels were significantly lower than in the control group. A high frequency of abnormalities of the plasma cortisol pattern was also found in patients with suprasellar meningiomas and diencephalic tumours. In cases with tumours of the sellar region a correlation was found between the occurrence of pathologically low plasma cortisol levels and rhythms and pathological results of the metyrapone test. In processes outside the sellar and diencephalic region there was no correlation between the localization of the lesion and a pathological plasma cortisol rhythm or level. It was found that increased intracranial pressure may give an abnormally high plasma cortisol level.