Registration Dossier

Ecotoxicological information

Toxicity to other aquatic organisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Additional information

Ovaries of adultX.laeviswere excised (stage V and VI) and exposed to different test concentrations of 2-phenoxyethanol in glass plates at 4°C for 24 hours in presence and absence of either progesterone or androstenedione. Germinal vesicle breakdown, as a marker of the final stage of amphibian oocyte maturation (oogenesis), was determined visually and was verified by cracking the fixed oocytes. Two independent triplicate measurements were conducted. The potency was expressed as IC25 at which 25% of progesterone or androstene­dione-induced GVBD occurred and was determined to be 1.9 and 5.3 µg/L for 2-phenoxyethanol, respectively.

Further, the binding capacity of 2-phenoxyethanol to oocyte plasma membrane receptor and to androgen was investigated by adding [3H]progesterone and [3H]androstenedione to the exposed oocytes. Oocytes or oocyte plasma membrane proteins were exposed (microinjected) with 2-phenoxyethanol equivalent to the IC25 and added radiolabeled hormones were separated from the oocytes or plasma by filtration or centrifugation. The OMPR and AR binding capacity of 2-phenoxyethanol was determined to be 10.8% relative to progesterone and 25.1% relative to androstenedione, respectively.

It was not investigated whether the effect concentrations are cytotoxic to the oocytes and 2-phenoxyethanol acted via both pathways (oocyte plasma membrane receptorand and androgen). This bimodal inhibition was unexpected and raised questions about the specificity of the assay with regard to the biological relevance.