Attempts to establish a screening procedure for endocrine disrupters by ovulation analysis using the intrabursal injection method

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he aim of this study was to establish the basis for a acreening method of endocrine disrupters using intrabursal injection analysis of mammalian ovulation.We first attempted to search for molecular markers suitable for this method. To this end, bradykinin B2 receptor and MMP-23(a new type of matrix metalloproteinase)were examined whether they would be appropriate as markers. The B2 receptor mRNA and receptor protein were both detected in the ovaries of pig and mouse. Further detailed morphological examination revealed that the B2 receptor mRNA was constitutively expressed in the granulosa cells of all growing follicles in the ovary, and that the mRNA levels did not change through the periovulatory period. These findings indicate that the B2 receptor may not serve as an appropriate marker. The expression of MMP-23 was examined using rat ovaries for the same purpose. MMP-23 mRNA was localized at granulosa cells of growing follicles in the early stages of follicle growth, but its expression was shifted to the outer thecal layer of fully grown follicles. Based on these results, we presumed that MMP-23 could be a marker for follicle growth rather than for ovulation.Effects of two known endocrine disrupters, DES and DEHP, on ovulatory process were examined by applying for the ovulation analysis method using female rats and mice. Intrabursal injection of DES and DEHP into rats did not resulted in significant decrease in the numbers of ovulated eggs. However, female offsprings of the DES-treated mother mice ovulated substantially reduced numbers of eggs. These results indicate that DES treatment affected profoundly reproductive ability of the offspring.