Stability of red cell antigens and plasma coagulation factors stored in a non-diethylhexyl phthalate-plasticized container

Diethylhexyl phthalate impairs insulin binding and glucose oxidation in Chang liver cells

The present study examined the dose-dependent effects of diethylhexyl phthalate (DEHP) on insulin receptor concentration and glucose oxidation in Chang liver cells. Chang liver cells (5 x 10(5) cells) were exposed to different concentrations (0, 50, 100, 200 and 400 microM) of DEHP for 24h. At the end of exposure, cells were utilized for assessing insulin receptor concentration and glucose oxidation. Both insulin receptor concentration and glucose oxidation in Chang liver cells were significantly reduced by high doses (200 and 400 microM) of phthalate exposure. The present study is first of its kind to report the direct adverse effects of DEHP on insulin receptor and glucose oxidation in Chang liver cells and suggests that DEHP exposure may have a negative influence on glucose homeostasis.

A glucose-regulated protein, GRP58, is down-regulated in C57B6 mouse liver after diethylhexyl phthalate exposure

Diethylhexyl phthalate (DEHP) is a widely used plasticizer that induces peroxisome proliferation in rodents. Prolonged exposure to DEHP results in a variety of toxic effects, the most significant of which appears to be an increased incidence of liver cancer and male reproductive toxicity in rodents. Accompanying these toxic effects is the induction of a number of genes within the liver, particularly those genes involved in peroxisomal fatty acid beta-oxidation and members of the cytochrome P450 family, CYP4A. In order to explore which additional genes may be altered by DEHP exposure, mRNA differential display was performed using total liver RNA from male C57B6 mice that were treated with either O or 2% DEHP in their diet for 7 days. In doing so, a number of partial cDNAs representing messages that are potentially differentially expressed have been isolated. One of these cDNAs was found to be similar to the previously cloned gene, GRP58. Analysis by RNase protection assay and North hybridization have shown that the transcript for GRP58 is down-regulated in the liver after DEHP exposure. Analysis of dose-response exposures to DEHP by reverse transcription (RT)-PCR confirm these results and also shows that GRP58 is not altered in kidney or testis. Immunoblot analysis using GRP58-specific antibodies also shows a decrease in GRP58 protein levels in DEHP-treated mice. Moreover, exposure of mice to another peroxisome proliferator, clofibrate, results in a slight down-regulation of GRP58 at the highest dose, 0.5%. Thus, it appears as if DEHP and clofibrate can use different pathways to affect gene expression.