Abstract
The enzyme 5alpha-reductase 1 (5α-R1) that converts testosterone (T) to dihydrotestosterone (DHT) is present in many mammalian tissues including the spinal cord. It is established that morphine administration decreases spinal cord T levels, but the mechanism is still undetermined. Here, we investigated the link between T and the enzyme 5α-R1 in the spinal cord after morphine administration. For spinal cord steroid extraction, all the animals were killed 30 min, 2 h (acute) and 14 days (chronic) after first drug injection by decapitation. The whole spinal cord was removed and kept frozen at −20°C until T and DHT extraction. The effects of acute and chronic morphine administration on 5α-R1 expression in the adult male rat spinal cord were evaluated using RT-PCR. Spinal cord T and DHT levels were measured using radioimmunoassay before and after the morphine exposure. Morphine significantly reduced the T concentration after acute and chronic exposure in the spinal cord. In contrast, the 5α-R1 expression and of course DHT levels increased the following chronic morphine administration. One important reason for the decreasing effect of morphine exposure on the spinal cord T level is due to an increase in the 5α-R1 levels. We suggest that morphine plays a regulatory role in metabolism of neurosteroids, especially T in the spinal cord via 5α-R1.
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Acknowledgments
This work is based on our present study on Opioids and Neural Stem Cells in the Laboratory of Tissue engineering and Stem cell, Research Center for Sciences and Technology in Medicine (RCSTiM) in Tehran University of Medical School, Tehran, Iran. Funding for this study is provided by the Research Center for Sciences and Technology in Medicine (RCSTM), Tehran University of Medical Sciences.
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Sharif, A., Shoae-Hassani, A., Sharif, S. et al. 5α-reductase 1 regulates spinal cord testosterone after morphine administration. Neurol Sci 34, 19–23 (2013). https://doi.org/10.1007/s10072-012-0936-x
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DOI: https://doi.org/10.1007/s10072-012-0936-x