Formation and persistence of DNA adducts in epidermal and dermal mouse skin exposed to benzo(a)pyrene in vivo.

Tritiated benzo(a)pyrene was applied topically to 35 old male Swiss mice that received 250 nMole (0.63 mCi) per mouse in 150 microliters acetone. At each time point of study, 1, 3 and 7 days, 10 animals were killed, the skin was removed and the susceptible epidermic cells were separated from resistant dermis.

[Specific induction by phorbol ester of the gene transcription and of the activity of ornithine decarboxylase in two control and transformed epithelial cell lines. Modulator effect of anti-inflammatory agents].

The mechanism of ornithine decarboxylase (ODC) induction by phorbol ester (TPA) has been studied in two permanent epithelial cell lines, a control (Ctr) and a Benzo (a) pyrene transformed line (BaP-tr); the degree of ODC gene expression (ODC-mRNA) was evaluated in comparison to the ODC activity. A small dose of TPA (4 x 10(-8) M) highly induced ODC activity in these cells. The induction levels differed however, corresponding respectively to 4:1 (induced: basal ODC) in Ctr cells and to 2:1 in BaP-tr cells.

Inhibition of chemically-induced skin carcinogenesis in mice by peanut oil preparations.

Epidermal hyperplasia and sebaceous gland destruction - good indicators of carcinogenic potential - were studied in short-term mouse skin experiments following application of BaP and TPA dissolved either in a peanut oil mixture or in acetone. Subsequently, the carcinogenicity of BaP and DMBA alone or in association with TPA was dissolved in the same vehicles, and determined in mouse long-term skin tests. In parallel, ODC activity and binding to DNA, RNA and proteins were examined in epidermal cells after exposure to TPA and BaP respectively.

1-Chloromethylpyrene: a reference skin sensitizer and genotoxin.

1-Chloromethylpyrene (1-CMP) has been evaluated as a model mutagen and toxin related to the ultimate electrophiles derived from benzo[a]pyrene and 1-nitropyrene. It was mutagenic to Salmonella (greater than 100 pg/plate) and exceptionally reactive to DNA when assessed by the 32P-postlabelling technique. 1-CMP was inactive in a mouse bone micronucleus assay when administered by gavage, probably due to hydrolysis, whose kinetics have been studied (t1/2 approximately 23 min at 37 degrees C).

Study of various transforming effects of the anabolic agents trenbolone and testosterone on Syrian hamster embryo cells.

Trenbolone, a synthetic androgen together with testosterone, a natural androgen, were studied comparatively for their transforming effects on Syrian hamster embryo (SHE) cells. The data indicated that both androgens exhibited weak positive complete transforming activities without a dose response relationship. Trenbolone is more toxic than testosterone when the concentrations tested are higher than 10 micrograms/ml, but is less able to transform SHE cells.