Section 5
Chapter 4,646

Abnormal limb regeneration without tumor production in adult newts cynops pyrrhogaster directed by carcinogens 20 methyl cholanthrene and benzo a pyrene

Tsonis, P.A.; Eguchi, G.

Development Growth and Differentiation 24(2): 183-190


ISSN/ISBN: 0012-1592
Accession: 004645467

The effects of the potent carcinogens 20-methylcholanthrene (MC) and benzo(a)pyrene (BP) on limb regeneration were studied in adult newts. A microcrystal of these carcinogens was administered directly to the blastema of forelimbs on day 7 after amputation. The formation of the regeneration cone was delayed and the cone was shifted abnormally in polarity depending on the site of microcrystal administration. These carcinogens affected morphogenesis of skeletal structures of regenerating limbs. Subregeneration and superregeneration of either or both carpals and digits, absence of either or both ulna and radius, and accessory limb formation have been recorded as abnormalities caused by these carcinogens. Non-carcinogenic benzocompounds did not show such effects as those of MC and BP. The regeneration blastema of the limb appears to be resistant to carcinogenic effects of the carcinogens used since tumor formation has never been observed.

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