Epidermal Carcinogenesis in the Mouse by Intraperitoneally Administered Urethane Followed by Repeated Applications of Croton Oil
1957; Springer Nature; Volume: 11; Issue: 2 Linguagem: Inglês
10.1038/bjc.1957.28
ISSN1532-1827
Autores Tópico(s)Olfactory and Sensory Function Studies
ResumoEPIDERMAL carcinogenesis in the mouse has been divided into two stages (Berenblum, 1954).In the first, the skin is prepared so that in the second a suitable non-carcinogenic or weakly carcinogenic agent is able to elicit a high incidence of epidermal tumours in the prepared skin.Most of the agents found able to prepare the skin in this way have been applied topically, but in three instances the agent was given by another route.2-Acetylaminofluorene given by mouth (Ritchie and Saffiotti, 1955), 9,10-dimethyl-1,2-benzanthracene given orally, intraperitoneally or intravenously (Graffi, Scharsach and Heyer, 1955) and urethane given by mouth (Haran and Berenblum, 1956) have all been reported able to prepare mouse skin in this way.The present paper describes a fourth manner in which mouse skin can be prepared in this way by an agent which is not applied topically.Intraperitoneally administered urethane has been found adequate to prepare mouse skin so that subsequent topical applications of croton oil are able to elicit a higher incidence of papillomata than croton oil can elicit in unprepared skin. METHODVirgin, adult, female mice of the Swiss strain obtained from the Roscoe B. Jackson Memorial Laboratory, Bar Harbor, Maine, were used.In each experi- ment, the mice of the experimental and control groups were drawn at random from a common pool, all animals weighing about 20 g.The mice were fed Rockland Mouse Diet, being given food and water ad libitum.They were weighed weekly, but no abnormal alteration in their weight was noted at any time during the experiments."Urethan Merck" (Ethyl carbamate) U.S.P. (lot 6839) was injected as a 10 per cent w/v solution in distilled water, 0.3 ml.being given intraperitoneally. 01.croton.B.P.C. (Boot's Pure Drug Co., batch 5596A) was applied as a 5 per cent v/v solution in heavy liquid paraffin B.P. (British Drug Houses (Canada) lot 12578), being spread sparely over the whole back with a fine camel's hair brush.The painted area was kept shorn with electric clippers or scissors.Control mice in groups not painted with croton oil were clipped in the same way as those painted.The mice were examined twice a week, and any changes in the number, size, type or position of the tumours charted on special diagrams. EXPERIMENTALThe skin tumours all arose within the area painted with croton oil.All were papillomata when they first appeared, and most remained sessile papillomata of
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