Effect of aminoglutethimide on urinary cortisol and cortisol metabolites in adolescents with Cushing's syndrome.
The effect of aminoglutethimide (AG) 4 X 250 mg (670 mg/m2 daily by mouth) on the excretion of the free cortisol (radio-immunoassay) and of its metabolites THE, THF-allo THF, cortolone and beta-cortolone (gas chromatography on capillary column) was studied monthly during 3-5 months in four adolescents (one girl, three boys) aged  15.9-18 years with Cushing's syndrome due to bilateral adrenal hyperplasia, but without evidence of a pituitary tumour. Under AG, all compounds decreased to a minimum after 1-2 months. The decrease of THE- THF-allo THF was most marked, followed by cortolone-beta-cortolone and free cortisol. The sum of the conjugated metabolites was normalized, but free cortisol remained high. A rebound was noted after 3-5 months of continued treatment. This was associated with clinical relapse (weight gain, increasing blood pressure). With AG, a non-steroidal peak appeared on the chromatograms. It is concluded that: (1) AG is only temporarily effective in diminishing the excretion of cortisol and its metabolites; (2) paradoxical increments of 17-ketosteroids as reported from colorimetric analysis are non-specific and are probably due to the non-steroidal peak; and (3) AG appears to modify steroid catabolizing liver enzymes (inhibition of 5beta-reductase and/or 3alpha-dehydrogenase, possibly stimulation of 20alpha- and 20beta-dehydrogenases). This could increase the biological half-life of cortisol and contribute to the clinical rebound, which is due to increased ACTH-secretion. Because of its excellent short-term effects, AG appears to be useful to prepare patients for bilateral adrenalectomy.
D000293:Adolescent; D000616:Aminoglutethimide / Q000627:therapeutic use*; D003480:Cushing Syndrome / Q000188:drug therapy*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism* / Q000652:urine; D008297:Male; D013997:Time Factors
D000616:Aminoglutethimide; D006854:Hydrocortisone