Influence of Tributyltin (TBT) on Level of Free Testosterone in Two Species of Neogastropods Found Along the Coast of Pakistan.

Abstract

Organotin compounds are used in antifouling paints and wood preservatives to prevent fouling of marine organisms on ships and other marine structures. The leaching of these compounds has caused imposex (pseudohermaphroditism) globally in females of over 170 species of prosobranch gastropods inhabiting areas close to marinas and harbours. The investigations of imposex induction pathway indicate that tributyltin (TBT) and triphenyltin (TPhT) produce this abnormality via endocrine dysfunction, interfering with the regulation of testosterone. The two gastropod species Thais bufo and T. rudolphi were analyzed from Manora Rocky Ledge, Clifton and Gadani Ship Breaking Yard. At Gadani Ship Breaking Yard the incidence of imposex was 100% while at the other two sites no imposex female was encountered. The testosterone levels were analyzed by using radio immunoassay (RIA). Higher levels of testosterone were recorded in imposex females than males at Gadani Ship Breaking Yard. However, from Clifton and Manora Rocky Ledge, elevated concentrations of testosterones were noted in males as compared to females. The relatively higher level of testosterone in imposex females from Gadani Ship Breaking Yard area indicates that TBT is an active biocidal agent released into marine environment during ship recycling process and is responsible for development of imposex and leading to elevated level of free testosterone in targeted species.