EFFECTS OF A MIXTURE OF NON-ORTHO-AND MONO-ORTHO-POLYCHLORINATED BIPHENYLS ON REPRODUCTION IN FUNDULUS-HETEROCLITUS (LINNAEUS)

To assess the effects of polychlorinated biphenyls (PCBs) on reproduct ion, female Fundulus heteroclitus were exposed to a mixture of non-ort ho- and mono-ortho-PCBs. mimicking the mixture found in fish collected from New Bedford Harbor, Massachusetts, USA, a PCB-contaminated estua ry. Exposure was by intraperitoneal injection of the mixture dissolved in corn oil. Doses of 0.76, 3.8, and 19 mu g PCB mixture per gram of wet weight produced liver concentrations of 2.99, 12.2, and 32.8 mu g non-ortho- and mono-ortho-PCBs per gram of dry liver, with dioxin toxi c equivalency concentrations (TEQs) of 0.063, 0.409, and 0.720 ng/g, r espectively. Female mortality was 58%, and egg production was reduced by 77% at the highest dose, compared to controls. Food consumption dec lined with increasing PCB concentration, suggesting that PCBs act indi rectly to reduce fecundity through an energetic effect. Pituitary gona dotropin content appeared to be suppressed at the highest dose, but th e ability of ovarian follicles to produce estradiol and testosterone i n vitro was not impaired. Significant residue-effects linkages were fo und, with TEQ emerging as a potential indicator of adverse effects. Mo rtality was directly related, and egg production was inversely related to log(10)TEQ. Multiple regression analysis indicated that egg produc tion was directly related to pituitary gonadotropin content and food c onsumption.