Effects of high-dose ketoconazole and dexamethasone on ACTH-stimulated adrenal steroidogenesis in orchiectomized prostatic cancer patients.
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The effects of high-dose ketoconazole (i.e. 400 mg every 8 h) therapy on adrenal steroidogenesis were investigated in 7 patients with advanced prostatic cancer who no longer responded to orchiectomy. An ACTH challenge was performed before and on days 14 and 28 of high-dose ketoconazole treatment. During the last 14 days, dexamethasone (0.5 mg twice daily) was administered together with ketoconazole. High-dose ketoconazole alone lowered the basal levels of the androgens by 49-66%. It almost completely inhibited their stimulation by ACTH, whereas plasma progesterone was doubled. Basal cortisol was only slightly lowered, but the response to ACTH stimulation was markedly blunted. Basal and stimulated plasma aldosterone remained unaffected. Both basal and stimulated 11-deoxycortisol, 11-deoxycorticosterone, and, to a lesser extent, corticosterone rose more markedly after ketoconazole than after placebo. The basal and stimulated plasma adrenal androgen levels were further reduced after combined ketoconazole-dexamethasone treatment, whereas plasma corticosterone, 11-deoxycortisol, and 11-deoxycorticosterone were lowered in the same way as cortisol. Aldosterone and progesterone profiles were similar to those observed under high-dose ketoconazole, but plasma 17 alpha-hydroxyprogesterone increased more markedly than after high-dose ketoconazole alone. These results demonstrate that high-dose ketoconazole lowers plasma androgen levels in orchiectomized patients and partly inhibits the gluco- and mineralocorticoid syntheses, especially after ACTH-stimulation. The addition of dexamethasone does not only correct the possible consequence of the impairment of the cortisol production by high-dose ketoconazole, but it further reduces the androgen levels and lowers the plasma concentrations of most precursors, for instance 11-deoxycorticosterone, which has some physiological mineralocorticoid activity.(ABSTRACT TRUNCATED AT 250 WORDS)
