Effects of mitotane treatment on human steroid metabolism: implications for patient management

L Ghataore, I Chakraborti, S.J.B. Aylwin, Klaus-Martin Schulte, Dorota Dworakowska, P Coskeran, Norman F. Taylor

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Mitotane (o,p'-DDD), an oral adrenolytic agent for treatment of advanced adrenocortical carcinoma (ACC), is reported to inhibit cortisol biosynthesis in vitro and enhance production from exogenous cortisol of urinary 6β-hydroxycortisol and unidentified polar unconjugated metabolites. We examined urinary steroid profiles by gas chromatographymass spectrometry of patients with histologically confirmed ACC following surgery, receiving a) hydrocortisone alone (three males and three females) and b) mitotane and hydrocortisone (six males and 11 females). Samples were collected after plasma mitotane had reached the therapeutic range of 1420mg/l. Increased excretion of polar unconjugated steroids during mitotane treatment was confirmed, with 6β-hydroxycortisol and 6β-hydroxy-20-dihydrocortisols predominating. The proportion of additionally hydroxylated metabolites was <2% in untreated controls and 52, 3552% (mean, range) in the mitotane plus hydrocortisone group. Ratios of 5α-/5β- and 20β-/20α-metabolites of administered cortisol were decreased 50-, 15-fold, and 14-, 8-fold respectively (males, females mean values) but with no change in metabolite ratios that reflect oxidoreduction at C11 or C20. Patterns of decrease in 5α- relative to 5β-reduced metabolites were similar to those of patients with 5α-reductase 2 deficiency or on treatment with the 5α-reductase 2 inhibitor finasteride but different from those of patients on dutasteride, indicating specific inhibition of 5α-reductase 2. We conclude that mitotane causes consistent changes in cortisol catabolism, most of which have not been previously recognised. These need not interfere with early detection of ACC recurrence. Induction of 6β-hydroxylation offers an explanation for a reported decrease in cortisol bioavailability. Mitotane also has potential as a unique steroid metabolic probe for 20β-reduction.
    Original languageEnglish
    Pages (from-to)37-47
    JournalEndocrine Connections
    Volume1
    Issue number1
    DOIs
    Publication statusPublished - 2012

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