Assessment of the toxic and potential teratogenic effects of four glycol ethers and two derivatives using the hydra regeneration assay and rat whole embryo culture.

The widespread use of the glycol ethers as solvents in manufacturing industries presents a vast potential for occupational exposure. In the present study the potential hazards of four glycol ethers and two derivatives were assessed using two in vitro tests, rat whole embryo culture and the hydra regeneration assay. Concentrations used ranged from 0.3 to 1.0 mg/ml in embryo culture and from 0.03 to 80.0 mg/ml in the hydra assay. The embryotoxic potential of the ethylene glycol mono-alkyl ethers was shown to increase with the length of the alkyl chain. This is in contrast to in vivo data but can be explained by the lack of maternal metabolism in the in vitro systems. However, the teratogenic hazard ratings obtained in the hydra assay and the types of malformations observed in embryo culture support in vivo data. Results obtained for diethylene glycol monoethyl ether are in agreement with in vivo data. Results of both assays suggest that ethylene glycol monosalicylate presents a significant potential teratogenic hazard and that ethylene glycol tetra-acetic acid presents toxic and teratogenic potentials. When the effects of maternal toxicity and metabolism are considered, the overall picture presented by the present results is one of general agreement with in vivo data.

Effects of female sex hormones in whole embryo culture.

Much work has been done in vivo on the effects of sex steroids on the developing foetus. Many genital anomalies have been reported; defects of other organ systems have been suggested. Synthetic oestrogens are considered to be developmental toxicants in vivo, while natural oestrogens are thought to present little or no risk. A small selection of hormones (17beta-oestradiol, 17alpha-ethynyloestradiol, diethylstilboestrol and progesterone) was tested using the rat whole embryo culture technique to see whether this difference could also be confirmed in vitro. Dysmorphogenic embryotoxic effects were evident with both natural and synthetic oestrogens, but at much higher concentrations than would be expected to circulate in humans after therapeutic use.