Impact of the exposure to 5alpha-dihydrotestosterone (DHT) on the pejerrey sex differentiation process.

GONZALEZ, A.; JUAN IGNACIO FERNANDINO; GUSTAVO MANUEL SOMOZA

Cumana

Congreso; X Congreso de la Sociedad de Toxicología y Química Ambiental de Latinoamérica (SETAC-LA); 2011

SETAC LA

Superficial water contamination with endocrine disruptors (ED) has been of great concern in the last years because these compounds can distort normal function of organisms at the endocrine level. The argentine pampasic region is characterized by the presence of shallow lakes. These water bodies are particularly susceptible to the impact of sewage effluents from neighbor human settlements. Sewage treatment systems, in case they exist, are generally unable to remove natural or synthetic steroids. Testosterone (T) and its metabolite 5α-Dihydrotestosterone (DHT) are the main anthropogenic androgens found in this type of effluents. In this context, the aim of this work was studying the impact of DHT during the sex determination/differentiation period in pejerrey (Odontesthes bonariensis) larvae. Larvae were obtained from a captive brood-stock and fed with 0.1 and 10 µg/g of DHT supplemented food from hatching, during 6 weeks. The larvae were then raised until week 11 when the experiment ended and sex ratio and gonadal maturation stage were analyzed by histology. Male percentage in control, 0.1 µg/g and 10 µg/g DHT was 60%, 59.1% and 81.8% respectively, presenting a male-biased ratio at the highest DHT concentration. In addition, males exposed to the highest DHT dose showed an increase in the number of germ cells when compared to control males, suggesting the induction of an early spermatogenesis. Furthermore a delay in the ovarian morphogenesis and an increase in the appearance of undifferentiated gonadal primordia were observed in those larvae exposed to DHT 0.1 µg/g. Taken together these results suggest that the exposure to DHT alters the sex and gonadal differentiation process in this species.