The Occurrence of Spontaneous Lymphomas but Not Adenomas or Sarcomas in Rats Treated With Sustained Release NaltrexoneErin Kelty1,3*, Philip K. Nicholls2, George O’Neil1,3, Zoe Harrison3, Chin-Tark Chan1,3, Peter Symons3, Albert Stuart Reece1,4 and Gary Hulse1
1Unit for Research and Education in Drugs and Alcohol, School of Psychiatry and Clinical Neurosciences (MDP 521), The University of Western Australia, Stirling Highway, Crawley, Western Australia, 6009
- *Corresponding Author:
- Erin Kelty
Go Medical Industries Ltd Pty
200 Churchill Road, Subiaco
WA 6008, Australia
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Received Date: November 25, 2011; Accepted Date: January 02, 2012; Published Date: April 21, 2012
Citation: Kelty E, Nicholls PK, O’Neil G, Harrison Z, Chan CT, et al. (2012) The Occurrence of Spontaneous Lymphomas but Not Adenomas or Sarcomas in Rats Treated With Sustained Release Naltrexone. Clin Exp Pharmacol 2:105. doi: 10.4172/2161-1459.1000105
Copyright: ©2012 Kelty E, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Naltrexone has been observed to have both a stimulatory and inhibitory effect on the development of tumours in rodents, potentially mediated by changes to the neuroendocrine system as a result of blockade of the opiate receptors, with the period of blockade and the tumour type thought to be influential. This study examined the occurrence of spontaneous tumours in rats treated with a sustained release naltrexone preparation. Materials and methods: 27 male and 27 female rats were randomized into three equal treatment groups (A, B and C). Rats in group A were implanted with a single naltrexone implant tablet, rats in group B were implanted with a single polymer implant tablet (placebo) and rats in group C underwent a sham procedure (control). Three different groups of spontaneous tumours were observed; lymphomas, adenomas and sarcomas. Lymphomas (4 tumours/3 rats) were observed solely in naltrexone treated rats, while adenomas (9 tumours/5 rats) and sarcomas (4 tumours/3 rats) were only observed in the placebo and the control groups. The data suggests that the association of naltrexone on the development of tumours maybe dependent on tumour type. Long term exposure to naltrexone appears to have both a stimulatory and inhibitory effect on tumours in rats, dependent on tumour type.