The tumor promoting activity of the EP4 receptor for prostaglandin E2 in murine skin.

To determine whether the EP4 receptor for prostaglandin E2 (PGE2) contributes to the tumor promoting activity of PGs in murine skin, EP4 over-expressing mice (BK5.EP4) were generated and subjected carcinogenesis protocols. An initiation/promotion protocol resulted in 25-fold more squamous cell carcinomas (SCCs) in the BK5.

Species and gender differences in the carcinogenic activity of trimethylolpropane triacrylate in rats and mice.

Trimethylolpropane triacrylate (TMPTA) is a multifunctional monomer with industrial applications. To determine the carcinogenic potential, male and female F344/N rats and B6C3F1/N mice were administered TMPTA (0, 0.3, 1.

Toxicology and carcinogenesis study of senna in C3B6.129F1-Trp53 tm1Brd N12 haploinsufficient mice.

Senna is a pod or leaf of Senna alexandrina P. Mill and is used as a stimulant laxative. In the large intestine, bacterial enzymes reduce sennosides to rhein-9-anthrone, the active form for the laxative effect.

Metabolism and disposition of 2-methoxy-4-nitroaniline in male and female Harlan Sprague Dawley rats and B6C3F1/N mice.

The disposition of 2-Methoxy-4-nitroaniline (MNA) was investigated in male and female Harlan Sprague Dawley rats and B6C3F(1)/N mice following oral, intravenous, and dermal exposure to [(14)C]MNA at 2, 15, or 150 mg/kg. Clearance of MNA was investigated in male and female rat, mouse, and human hepatocytes. MNA was cleared slowly in hepatocytes from rat (t(1/2) = 152-424 min) and human (t(1/2) = 118-403 min) but faster in mouse (t(1/2)= 70-106 min).

Comparative dermal toxicity of dicyclohexylcarbodiimide and diisopropylcarbodiimide in rodents.

Dicyclohexylcarbodiimide (DCC) and Diisopropylcarbodiimide (DIC) are two representative chemicals in the carbodiimide class of chemicals used in industry as stabilizing agents. There is a potential of dermal exposure to these agents in chemical, pharmaceutical and recombinant DNA industries. The National Toxicology Program conducted a number of animal studies to characterize toxicity and carcinogenicity of DIC and DCC.

The EP1 receptor for prostaglandin E2 promotes the development and progression of malignant murine skin tumors.

High levels of prostaglandin E2 (PGE2) synthesis resulting from the up-regulation of cyclooxygenase (COX)-2 has been shown to be critical for the development of non-melanoma skin tumors. This effect of PGE2 is likely mediated by one or more of its 4 G-protein coupled membrane receptors, EP1-4. A previous study showed that BK5.

Upregulation of the EP1 receptor for prostaglandin E2 promotes skin tumor progression.

Prostaglandin E(2) (PGE(2) ) has been shown to promote the development of murine skin tumors. EP1 is 1 of the 4 PGE(2) G-protein-coupled membrane receptors expressed by murine keratinocytes. EP1 mRNA levels were increased ∼2-fold after topical treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) or exposure to ultraviolet (UV) light, as well as increased ∼3- to 12-fold in tumors induced by 7,12-dimethyl-benz[a]anthracene (DMBA) initiation/TPA promotion or by UV exposure.