Effects of Chinese Domestic Polychlorinated Biphenyls (PCBs) on Gonadal Differentiation in Xenopus laevis

• Published in: Environmental health perspectives Vol. 111; no. 4; pp. 553 - 556
• Main Authors: Qin, Zhan-Fen, Zhou, Jing-Ming, Chu, Shao-Gang, Xu, Xiao-Bai
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01.04.2003; National Institute of Environmental Health Sciences
• Subjects: Amphibians; Animals; Anura; Chemical hazards; Endocrine disruptors; Endocrine System - drug effects; Environmental Exposure; Environmental Pollutants - adverse effects; Female; Freshwater; Gonads; Gonads - growth & development; Histology; Intersex persons; Larva; Male; Metamorphosis, Biological - drug effects; Oocytes; Ovaries; Polychlorinated biphenyls; Polychlorinated Biphenyls - adverse effects; Testes; Xenopus laevis; Xenopus laevis - growth & development; China, People's Rep
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.5620

To determine whether polychlorinated biphenyls (PCBs) influence gonadal differentiation in Xenopus laevis, tadpoles were exposed to two Chinese domestic PCBs ( PCB3and PCB5) from Nieuwkoop and Faber stage 46/47 to complete metamorphosis. Gonads were characterized using a dissecting microscope. The control X. laevis had normal ovaries or testes in gross morphology, whereas obviously abnormal testes including ovotestes were found in PCB3- and PCB5-exposed groups. Ovotestes were characterized by morphologic ovaries in the cranial and caudal parts and morphologic testes in the middle part. PCBs did not alter the percentage of females but reduced the percentage of males with morphologically normal testes. The histologic structure of gonads was examined by a series of sections. Morphologically normal and abnormal testes from a few frogs exposed to PCBs were interspersed with oocytes in histologic sections. These testes exhibited looser structure with fewer seminiferous tubes, spermatogonia, and spermatozoa than in controls. The findings suggest that PCB3and PCB5have significant feminization effects on gonadal differentiation in X. laevis and that this species is sensitive to endocrine disruption and may be used as a good model to study endocrine disruption.