Steroid enzyme activities in extraadrenal pheochromocytomas.
The adrenal medulla and tumors derived from it have been shown to be capable of converting radioactive steroid intermediates into glucocorticoid end products in vitro. This capacity for partial steroid synthesis was explored in two large extraadrenal pheochromocytomas and compared to the results of parallel studies with intraadrenal pheochromocytomas and adrenal cortex; in one experiment, all three types of tissue were obtained from a single patient and studied simultaneously. Slice preparations of extraadrenal pheochromocytoma transformed 14C-labeled pregnenolone (3 beta-hydroxypregn-5-en-20-one) into corticosterone and cortisol. Incubations of subcellular fractions demonstrated that, as in the adrenal cortex and intraadrenal chromaffin tissue, delta 5-3 beta-hydroxysteroid dehydrogenase-isomerase, 17 alpha-hydroxylase, and 21-hydroxylase activities in extraadrenal pheochromocytomas were associated with the microsomes and 11 beta-hydroxylase was associated with the mitochondria, where metyrapone was an effective inhibitor, these findings tend to dissociate steroid-metabolizing activity in the adjacent chromaffin tissue perfused by glucocorticoid intermediates in high concentrations.
D000236:Adenoma / Q000201:enzymology*; D000302:Adrenal Cortex / Q000201:enzymology*; D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000306:Adrenal Cortex Neoplasms / Q000201:enzymology; D000310:Adrenal Gland Neoplasms / Q000201:enzymology*; D000328:Adult; D002395:Catecholamines / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D002838:Chromaffin System / Q000201:enzymology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000201:enzymology; D010673:Pheochromocytoma / Q000201:enzymology*; D011375:Progesterone Reductase / Q000378:metabolism; D013250:Steroid Hydroxylases / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D002395:Catecholamines; D002784:Cholesterol; D011375:Progesterone Reductase; D013250:Steroid Hydroxylases