STEROID CONTENTS AND CORTICAL STEROIDOGENIC ENZYMES IN NON-HYPERFUNCTIONING ADRENAL ADENOMA

The recent increasing use of ultrasound and computed tomography has re vealed numbers of incidentally discovered adrenal tumors. Many studies have focused on their surgical management, but the biological charact eristics of these adrenal tumors have remained unclear. Adrenal tumors were resected from 10 patients who underwent gastrectomy or cholecyst ectomy. No signs or symptoms of adrenal hormone excess or deficiency w ere evident either before or after the operation. Moreover, after surg ery, no major differences in signs and symptoms including blood pressu re levels were observed. Before surgery, neurogenic tumors and cysts w ere excluded by enhanced magnetic resonance imaging. Steroid contents and both the activities and amounts of steroidogenic cytochrome P-450s in the adrenocortical adenomas of these patients were examined. Micro scopic examination revealed that the tumors were surrounded by a thin, non-intact capsule; the surrounding cortex was not atrophic and appar ently normal; and the cells of both the tumor and adjacent portions we re arranged in nests and cords. Measurements of all steroid content (p regnenolone, progesterone, corticosterone, 11-deoxycorticosterone, 18- hydroxydeoxycorticosterone, cortisol, and dehydroepiandrosterone) exce pt aldosterone in 5 resected adrenal tumors were within the normal ran ges for the adrenals of 5 patients with renal cell carcinoma. Aldoster one content in tumor portions was significantly lower than in the appa rently normal adrenals. Although in both tumor and adjacent portions o f another 5 resected adrenal tumors the activities and amounts of cyto chrome P-450s (P-450(scc), P-450(11 beta), P-450(aldo), P-450(17 alpha ), and P-450(c21)) were also within the normal ranges, the activities of P-450(scc) and P-450(17 alpha) in the tumor portion were greater th an those in the adjacent portion. Grossly well-demarcated yellowish-br own tumors of the adrenal gland were observed in all the cases of adre nal tumor. The above results suggested that adrenal incidentalomas pro duce adrenal steroids through steroidogenic enzymes in both the tumor and adjacent portions. In addition, decreases in aldosterone content a nd increases in the activities of P-450(17 alpha) in tumor portions su ggest the shift of steroidogenesis from a mineralocorticoid pathway to a glucocorticoid pathway.