Aromatase and 5-alpha reductase gene expression: modulation by pain and morphine treatment in male rats.

Background: The steroid hormone testosterone has been found to be greatly reduced by opioids in different experimental and clinical conditions. The purpose of this study on male rats was to determine the effects of a single injection of morphine (5 mg/Kg) on persistent pain (formalin test) and the single or combined effects on p450-aromatase and 5-alpha reductase type 1 mRNA expression in the brain, liver and testis. Testosterone was determined in the plasma and in the brain, morphine was assayed in the plasma.

Effects of morphine on testosterone levels in rat C6 glioma cells: modulation by anastrozole.

Rat C6 glioma cells are commonly used to investigate the functions of glial cells. To evaluate the presence of testosterone and its metabolism in rat C6 glioma cells, we cultured them in media with or without the addition of testosterone propionate and anastrozole, a blocker of aromatase, the enzyme needed to transform testosterone into estradiol. The same procedure was repeated with morphine (10 and 100 microM), known to decrease testosterone levels in the brain (in rats) and plasma (in rats and humans).