Cushing syndrome with food-dependent periodic hormonogenesis

Periodic hormonogenesis has been described in patients with ACTH-dependent hypercorticism, and fluctuations of cortisol secretion have also been observed in patients with adrenal tumors. In this report, we studied a 41-year-old white male who presented with hypertension, central obesity, and muscle weakness of 2-years duration. His plasma cortisol was low (4.5 micrograms) in the morning and high in the evening (29.3 micrograms). Urinary free cortisol was 750 micrograms/day. A 24-hour cycle demonstrated highest values at noon and in late afternoon. This pattern was not suppressed by dexamethasone. When the patient was kept fasting, plasma cortisol remained low all day, and became elevated immediately after meal administration overnight. A left-sided adrenal mass was demonstrated and removed. In vitro, the adenylate cyclase activity of tumor tissue demonstrated more significant response to vasopressin than to ACTH; other tested peptides were inactive. We propose that a humoral factor induced by eating was responsible for the periodic hormonogenesis, directly stimulating the adrenal secretion of cortisol.