Effects of Suramin on the Function and Structure of the Adrenal Cortex in the Cynomolgus Monkey

There have been reports of adrenal failure in patients treated with suramin, an agent that has recently been used as therapy for acquired immune deficiency syndrome. We conducted this study to assess the effect of suramin on adrenal function and structure in a primate, the cynomolgus monkey. Five male monkeys were treated with suramin (800 mg/m2, im) once a week, for 5 weeks. Five other animals (controls) received saline. The treated animals had progressive elevations of plasma ACTH (P less than 0.05) and PRA (P less than 0.02) and decreased serum cortisol responses 30 min after the administration of synthetic ACTH (P less than 0.05) compared to controls. There was disruption of the architecture of the adrenal cortex, a diffuse inflammatory cell infiltrate, and thinning of the zona glomerulosa and zona fasciculata in the suramin-treated animals. We conclude that suramin is toxic to adrenal cortical tissue and might be useful in treating conditions with adrenal cortical hyperfunction, such as adrenal cortical carcinoma and Cushing's syndrome.