Studies on the Specificity of Fluorimetric Determination of Plasma Corticosteroids ad Modum De Moor & Steeno

Abstract

The simple and convenient fluorimetric method of estimating cortisol in small volumes of plasma as described by De Moor et al. has been re-examined and compared with a specific isotope dilution method. It has been shown that there is a good correlation although values found by the less specific fluorimetric method are about twice as high.

The method was studied in detail and some investigations were done in an attempt to elucidate the problem of the unspecific fluorogens.

Diurnal variations in 18 normal persons and results of ACTH stimulations in 16 normal persons are mentioned and the results are compared with the findings of others using fluorimetric procedures.

The unspecific fluorogens and the influence of some interfering steroids are discussed and it is concluded that in spite of its unspecificity the method is well suited for following spontaneous diurnal variation in plasma cortisol, variation during ACTH stimulation, and dexamethasone suppression.

It is also a valuable supplement to the determination of 17-KGS in the metyrapone test.

Key Words:

• Adrenal cortex
• adrenal cortex function tests
• adrenal cortex hormones
• corticosterone
• hydrocortisone