Melatonin Shortens the Survival Rate of Ehrlich Ascites-inoculated Mice
by Sergiu-Bogdan Catrina, Elena Curca, Anca Irinel Catrina, Corina Radu & Mihai Coculescu
melatonin, malignancy, pineal low-molecular factor(s), Ehrlich ascites and survival rate
Submitted: November 1, 2001
Accepted: November 18, 2001
OBJECTIVES Pineal gland may have a role in organisms protection against cancer. Melatonin as well as still unidentified low-weight molecular pineal substance(s) have been reported to have growth inhibitory effect on different tumor cells. We tested the influence of melatonin and of a bovine pineal extract on the survival rate of AKR mice inoculated with Ehrlich ascites. The tumor is known to have an accelerated development after pinealectomy.
MATERIAL AND METHODS: Male AKR mice, kept under a 14/10 hours - Light /Dark cycle, were inoculated intraperitoneally (i.p.) with 1.5x 106 Ehrlich ascites cells. On day three after inoculation the animals were divided in three groups (n=10). Each animal received i.p. daily (20.00H), until their death, 250 ml of solution containing melatonin (250 mg), pineal extract (equivalent of 1 bovine pineal gland) or saline.
RESULTS: The average survival rate of the animals treated with melatonin was shorter (14.8+/-2.23 days) compared to control animals (21.9+/-2.21 days) (p=0.01). The animals treated with the pineal extract had a longer survival rate (22.6 +/- 1.8 days) but not statistically significant. The pineal extract was not available for testing at higher doses.
CONCLUSION: In our model, melatonin had a deleterious effect on the survival rate raising the question whether it is correct to assume that the hormone shows lack of adverse reactions.