Morphine and kisspeptin influences on 5α- reductase and aromatase gene expression in adult male rats

Objective(s): Kisspeptin and opioids are important factors for controlling GnRH/LH secretion. In present study, influences of kisspeptin or morphine were investigated on 5α- reductase or aromatase (CYP19) genes expression in the hypothalamus, testis and liver. It aimed to investigate whether kisspeptin pathway may control morphine effects on plasma concentration of testosterone. Materials and Methods: Twenty adult male rats in four groups received saline/saline, kisspeptin (1 nmol)/ saline, morphine (5 mg/kg)/saline or kisspeptin/morphine respectively. Mean relative 5α-reductase and aromatase mRNA levels were determined by RT-PCR. Results: Morphine/saline injection increased significantly mean relative mRNA levels of hypothalamic 5α-reductase or aromatase compared to saline/saline. While morphine/saline did not alter mRNA levels of them compared to saline/saline group in the testis and liver. Kisspeptin/saline did not significantly decrease mean relative 5α-reductase or aromatase genes expression compared to saline/saline group in the hypothalamus, testis and liver. Injections of kisspeptin/morphine did not significantly decrease mean relative 5α-reductase or aromatase genes expression compared to morphine/saline group. Conclusion: Up-regulation of hypothalamic 5α-reductase or aromatase mRNA levels may partly induce the inhibitory effects of morphine on GnRH/LH release. Different effects of morphine on aromatase or 5α- reductase genes expression levels in the liver and testis compared to brain may be partly due to different sensitivity or functions of them to morphine used dose.