Evaluation of a reproductive toxicity assay using Xenopus laevis: boric acid, cadmium and ethylene glycol monomethyl ether.

Cadmium (Cd), boric acid (BA) and ethylene glycol monomethyl ether (EGME) were evaluated for reproductive and developmental toxicity in Xenopus laevis. Eight reproductively mature adult male and eight superovulated female Xenopus laevis were exposed to at least five separate sublethal concentrations of each material via the culture water for a period of 30 days. Four respective pairs were mated and the offspring evaluated for developmental effects; an evaluation of reproductive status was performed on the remaining four specimens. Ovary pathology, oocyte count, oocyte maturity and maturation capacity (germinal vesicle breakdown, GVBD) and necrosis were evaluated in the female, whereas testis pathology, sperm count, dysmorphology and motility were studied in the male. Based on this assessment, each test material exerted reproductive toxicity in Xenopus laevis, but with varying potencies. Adult female exposure to Cd and EGME particularly, and to a lesser extent to BA, resulted in transgenerational toxicity to the developing progeny. Further, this model appears to be a useful tool in the initial assessment and prioritization of potential reproductive toxicants for further testing. Copyright 2001 John Wiley & Sons, Ltd.