Content and biosynthesis of cortisol in aldosterone-producing adenomas

Abstract

The content and biosynthesis of aldosterone and cortisol were examined and compared in the aldosterone-producing adenomas and adjacent adrenal glands from patients with primary aldosteronism that resulted from solitary, benign adrenocortical tumors (0.8 to 32.3 gm). Histologic examination of the six aldosterone-producing adenomas studied confirmed a predominance of cells resembling zona fasciculata rather than zona glomerulosa, as reported in previous studies. Measurement by radioimmunoassay of the tissue content of steroids preformed in vivo demonstrated that aldosterone was present in concentrations 8 times higher in aldosterone-producing adenomas (1.5 +/- 0.5 micrograms/gm tissue; mean +/- SEM) than in adrenal glands (0.2 +/- 0.06 micrograms/gm tissue). Cortisol concentration in aldosterone-producing adenomas (5.4 +/- 1.4 micrograms/gm tissue) was approximately one third that in adrenal glands (15.8 +/- 6.3 micrograms/gm tissue), but cortisol was by far the major steroid in both types of tissue. In vitro, the most important metabolic product quantitatively from 4-carbon 14-labeled cholesterol incubated with mitochondria plus microsomes and from 4-14C-labeled pregnenolone incubated with tissue slices was cortisol, formed in a time-dependent manner in both types of preparations; cortisol synthesis greatly exceed that of aldosterone in adrenal glands, but even in aldosterone-producing adenomas the formation of cortisol was at least 5 times greater than that of aldosterone. The fasciculata structure and dual biosynthetic capacity of aldosterone producing adenomas for cortisol and aldosterone are interpreted in the light of developing concepts of the roles of adrenocorticotropic hormone and of alterations in the microenvironment of the cell in the zonal differentiation of the normal adrenal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)