There are a number of detrimental exposures that are known to cause reproductive toxicity, and numerous others that are also likely to affect the reproductive system. In order to identify possible reproductive toxicants and study the mechanism(s) of action of those that are known, in vitro techniques have been and will continue to be important. This article will describe the currently available in vitro methods for examining ovarian toxicity. Examples will be given on how ovarian tissue cultures, cultures of individual ovarian follicles, and cell lines have been used to study exposures that affect the normal functioning of the ovary. The advantages and disadvantages of each technique will be discussed. Results that provide insight into the mechanisms of action of certain ovarian toxicants will be described to demonstrate the utility of each method.

This study was undertaken to characterize the toxicokinetics of p-tert-octylphenol (OP), a weak estrogenic compound, in male and female rats. Male and female Sprague-Dawley rats were given a single dose of OP either by oral gavage (50, 125 or 250 mg/kg), by intravenous (iv) injection (2, 4, or 8 mg/kg), or by subcutaneous (sc) injection (125 mg/kg). In a repeated dosing experiment, rats were given OP (oral) daily (25, 50, or 125 mg/kg) for 35 d (female) or 60 d (male). Blood and tissue samples were collected and analyzed for OP content using gas chromatography with detection by mass spectrometry. Blood OP concentrations were generally higher in female than male rats following a single oral or sc administration but were similar following a single iv injection. Tissue OP concentrations were also higher in female than male rats following oral exposure, consistent with the faster metabolism of OP observed in male rat liver microsomes. After subchronic administration, blood OP concentrations were higher at the end of exposure for female (33 d) (2.26-fold, not significant) and male (57 d) (3.47-fold) rats than single dosing but there was no change in the tissue OP concentrations. Gender differences in tissue OP concentrations may contribute, in part, to gender differences in the toxicity of OP in rats. The fact that OP was found in all reproductive tissues confirms its potential for direct endocrine-like effects.

A sensitive and reproducible procedure using gas chromatography coupled with mass spectrometry is described for the determination of p-tert-octylphenol (OP), a persistent degradation product of alkylphenol ethoxylates that binds to the estrogen receptor in blood and tissues. The first step involved the extraction of blood (200 microL) or tissue homogenate (400 microL) with methyl tert-butyl ether, including p-tert-butylphenol (BP) as internal standard. After extraction, the sample was evaporated to dryness with a gentle stream of nitrogen at 45 degrees C, and OP and BP were derivatized with an acetylation reaction involving acetic anhydride and catalyzed by pyridine. Samples were then analyzed by a gas chromatograph equipped with a mass spectrometer (single ion monitoring) with a Varian VF-5ms capillary column. The limit of detection and the limit of quantification of the method in blood were 4.6 and 15.5 ng/mL, respectively. The linearity and reproducibility of the method were acceptable, with coefficients of variation of approximately 10% for blood and ranging between 9% and 27% for tissues. This method was applied to the determination of unchanged OP in blood and tissues obtained from Sprague-Dawley rats after oral and IV OP administration.

Four methods of item bias detection-transformed item difficulty, item discrimination expressed as Clemans' lambda, ChiSquare, and the three-parameter item characteristic curve-were studied to determine the degree of correspondence among them in identifying biased and unbiased items in reading and math subtests of the 1978 SRA Achievement Series. Intercorrelations among the four methods were moderate at best, confirming previous research involving different item bias analysis techniques. The item discrimination method showed the least correspondence with the other three methods. The extent of overlap between the four item bias methods in identifying biased items depends on the extent of bias in the items comprising the initial pool of items. That is, except for the item discrimination method, the item bias procedures identify similar sets of most biased items.