Effects of pentachlorophenol on the reproduction of Japanese medaka ( Oryzias latipes)

Abstract

Pentachlorophenol (PCP) is widely used to control termites and protect wood from fungal-rot and wood-boring insects, and is often detected in the aquatic environment. Few studies have evaluated PCP as an environmental endocrine disruptor. In the present work, Japanese medaka ( Oryzias latipes) was exposed to PCP for 28 days (F0 generation) with subsequent measurements of vitellogenin (VTG), hepatic 7-ethoxyresorufin- O-deethylase (EROD), and reproductive endpoints. Plasma VTG significantly increased in male fish treated with PCP concentrations lower than 200 μg/l and decreased in male and female animals exposed to 200 μg/l. Hepatic EROD from female fish increased when PCP exposure concentrations exceeded 20 μg/l, but decreased in the 200 μg/l PCP treatment group. Fecundity and mean fertility of female medaka decreased significantly in the second and third week following exposure concentrations greater than 100 μg/l, and testis-ova of male medaka was observed at PCP concentrations greater than 50 μg/l. Histological lesions of liver and kidney occurred when exposure concentrations exceeded 50 μg/l. In F1 generations, the hatching rates and time to hatch of offspring were significantly affected in fish exposed to 200 μg/l. These results indicated that PCP exposure caused responses consistent with estrogen and aryl hydrocarbon receptor activation as well as reproductive impairment at environmentally relevant concentrations.