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Adrenal enkephalin biosynthesis regulated by glucocorticoid
C Inturrisi1, S Franklin, J Shapiro
1Department of Pharmacology, Cornell University Medical College, New York, New York.
NIDA Research Monograph
|January 1, 1988
Summary
Denervation increases adrenal enkephalin-containing (EC) peptides, a rise blocked by hypophysectomy but restored by glucocorticoids. This highlights the role of glucocorticoids in EC peptide biosynthesis regulation.
Area of Science:
- Neuroendocrinology
- Molecular Biology
- Adrenal Gland Physiology
Background:
- Adrenal medullary cells synthesize enkephalin-containing (EC) peptides.
- Regulation of EC peptide biosynthesis involves neural and hormonal factors.
Purpose of the Study:
- To investigate the role of denervation and hormonal factors in regulating EC peptide biosynthesis in rat adrenal medulla.
- To elucidate the pretranslational control of EC peptide expression.
Main Methods:
- Rat adrenal denervation surgery and hypophysectomy.
- In vitro culture of adrenal medullary explants.
- Hormonal treatments with dexamethasone and ACTH.
- Measurement of EC peptide levels.
Main Results:
- Denervation of rat adrenal glands caused a 10-20 fold increase in EC peptides.
- Hypophysectomy blocked this denervation-induced rise.
- Dexamethasone or ACTH partially restored EC peptide levels.
- In vitro, dexamethasone significantly increased EC peptides in explants from hypophysectomized rats.
Conclusions:
- Loss of depolarizing stimuli (denervation/explantation) initiates a pretranslational event for EC peptide biosynthesis.
- Glucocorticoids are essential for the full expression of EC peptide biosynthesis.
- This study reveals a critical role for glucocorticoids in regulating neuropeptide production in the adrenal medulla.