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Steroid enzyme activities in extraadrenal pheochromocytomas
The Journal of Clinical Endocrinology and Metabolism
|March 1, 1982
Summary
Extra-adrenal pheochromocytomas can partially synthesize steroids, converting pregnenolone into corticosterone and cortisol. This steroidogenesis occurs in specific subcellular fractions, similar to adrenal cortex tissue.
Area of Science:
- Endocrinology
- Molecular Biology
- Oncology
Background:
- Adrenal medulla and its tumors can convert steroid intermediates into glucocorticoids.
- Previous studies focused on intraadrenal tissues.
Purpose of the Study:
- To investigate the steroid synthesis capacity of extraadrenal pheochromocytomas.
- To compare this capacity with intraadrenal pheochromocytomas and adrenal cortex.
Main Methods:
- Incubation of extraadrenal pheochromocytoma slices with 14C-labeled pregnenolone.
- Study of subcellular fractions from pheochromocytomas and adrenal cortex.
- Enzyme activity assays for steroidogenic enzymes.
Main Results:
- Extraadrenal pheochromocytomas converted pregnenolone to corticosterone and cortisol.
- Specific hydroxylase activities were localized to microsomal and mitochondrial fractions.
- Metyrapone inhibited mitochondrial 11 beta-hydroxylase activity.
Conclusions:
- Extraadrenal pheochromocytomas possess partial steroidogenic capabilities.
- Steroidogenic enzyme localization in extraadrenal tumors mirrors that of the adrenal cortex.
- These findings suggest localized steroid metabolism within chromaffin tissue.