ISSN:
1432-2307
Keywords:
Tumor promotion
;
Tumor initiation
;
DMBA
;
TPA
;
Two-stage carcinogenesis experiment
;
Carcinogenesis
;
Cocarcinogenesis
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary In contrast to a previous report by Shubik, the validity of the 2-stage skin carcinogenesis experiment was demonstrated in the rat. The modified experiment was carried out in female Sprague-Dawley rats using intragastrically administered DMBA as a carcinogen and the topically applied phorbol ester TPA as a promoter. Seven groups of animals were used. Two groups were treated with TPA only, two groups were initiated only with DMBA, two further groups were both initiated and promoted, and one group served as a control. Each of the initiated/promoted groups or only initiated or promoted groups contained one sub-group in which the animals had been bilaterally ovarectomized prior to the experiment. Hyperplasia of the dorsal epidermis occurred only in the promoted and in the initiated/promoted groups. Tumors of the back skin were observed exclusively after initiation/promotion. Ovarectomy — leading to a prolonged survival time of the animals — seems to be crucial for the manifestation of malignant skin tumors. Initiation/promotion also gives rise to tumors of the forestomach, the small intestine, the liver and the colon. Tumors in other organs (especially in the mammary gland and the Zymbal gland) were also be observed after initiation alone.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00427403
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