5[alpha]-reductase 1 regulates spinal cord testosterone after morphine administration

• Published in: Neurological sciences 2013-01, Vol.34 (1), p.19
• Main Authors: Sharif, Alireza, Shoae-hassani, Alireza, Sharif, Shiva, Banafshe, Hamid Reza, Mortazavi-tabatabaei, Seyed Abdolreza, Verdi, Javad
• Format: Article
• Language: English
• Subjects: Neurology; Neurosciences
• ISSN: 1590-1874; 1590-3478
• DOI: 10.1007/s10072-012-0936-x

The enzyme 5alpha-reductase 1 (5[alpha]-R^sub 1^) 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 5[alpha]-R^sub 1^ 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 5[alpha]-R^sub 1^ 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 5[alpha]-R^sub 1^ 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 5[alpha]-R^sub 1^ levels. We suggest that morphine plays a regulatory role in metabolism of neurosteroids, especially T in the spinal cord via 5[alpha]-R^sub 1^.[PUBLICATION ABSTRACT]