Abstract
Objective
We hypothesized that in addition to dehydroepiandrosterone (DHEA) depletion, Sjögren’s syndrome (SS) is characterized by local androgen deficiency in salivary glands and defects in local processing of DHEA.
Methods
Sex steroid levels in serum and saliva were measured using enzyme immunoassays. Androgen effects on salivary gland cells were analyzed using the cysteine-rich secretory protein-3 (CRISP-3) androgen biomarker.
Results
Serum and salivary concentrations of androgens were low in SS. Substrate to end-product ratios and correlations suggest that in SS salivary glands DHEA is effectively converted to testosterone, but that there are defects in converting testosterone further to dihydrotestosterone (DHT). In healthy controls no such phenomenon was seen, but testosterone is effectively converted to DHT. Salivary glands contained type I 5-α-reductase, and its inhibition with dutasteride completely blocked the upregulating effect of DHEA, but not of DHT, on CRISP-3 in human salivary gland acinar cells.
Conclusion
DHEA and DHT upregulate CRISP-3, which is reportedly low in SS. The effect of DHEA on CRISP-3 is indirect and is inhibited by dutasteride, showing that there is intracrine processing of DHEA in salivary glands. In healthy glands, but not in SS, DHEA is effectively taken up and converted to DHT. Sex steroid concentrations in saliva in part reflect glandular uptake of DHEAsulfate and local intracrine DHEA metabolism, which seem to be defective in SS. Our study demonstrates a prominent androgen deficiency and a defect in intracrine production of active androgens in SS salivary glands, also suggesting that salivary DHT cannot be maintained at a normal level in this female-dominant autoimmune exocrinopathy.
Key Indexing Terms:Footnotes
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P. Porola, MSc, Institute of Clinical Medicine, Biomedicum Helsinki; L. Virkki, MSc, Institute of Clinical Medicine, Biomedicum Helsinki and ORTON Orthopaedic Hospital of the Invalid Foundation; B.D. Przybyla, PhD, Institute of Aging, University of Arkansas for Medical Sciences; M. Laine, MD, DDS, Institute of Clinical Medicine, Biomedicum Helsinki and COXA Hospital for Joint Replacement; T.A. Patterson, MD, Division of Neurotoxicology, University of Arkansas for Medical Sciences; A. Pihakari, MD, DDS, Helsinki City Health Department, Teaching Clinic; Y.T. Konttinen, MD, PhD, Professor of Medicine, ORTON Orthopaedic Hospital of the Invalid Foundation, COXA Hospital for Joint Replacement, and Department of Medicine, Hospital District of Helsinki and Uusimaa.
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Supported by the Academy of Finland, Victoriastiftelsen, Finska Läkaresällskapet, evo grants, and Orion-Farmos Research Foundation.
- Accepted for publication July 3, 2008.