Thyroxine Increases Stomach Cancer in Rats
Author Information
Author(s): H. Iishi, M. Tatsuta, M. Baba, R. Yamamoto, H. Taniguchi
Primary Institution: The Center for Adult Diseases, Osaka
Hypothesis
Does L-thyroxine enhance gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats?
Conclusion
Long-term treatment with thyroxine significantly increased the incidence of gastric cancers in rats without affecting their histological type.
Supporting Evidence
- Rats treated with thyroxine had a higher incidence of gastric cancers compared to those treated with olive oil.
- All tumors found were classified as adenocarcinomas, mostly very well-differentiated.
- Thyroxine treatment increased the labelling indices of gastric mucosal epithelial cells.
Takeaway
Giving rats a hormone called thyroxine made them more likely to get stomach cancer after being treated with a chemical that causes cancer.
Methodology
Sixty male Wistar rats were treated with a carcinogen for 25 weeks, followed by injections of thyroxine or olive oil until week 52, after which they were examined for gastric cancers.
Potential Biases
Potential bias in histological examination as the evaluators were not blinded to the treatment groups.
Limitations
The study was limited to male Wistar rats and may not be generalizable to other populations.
Participant Demographics
Sixty 6-week-old male Wistar rats.
Statistical Information
P-Value
p<0.05
Statistical Significance
p<0.05
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