Effects evoked by prenatal exposure to atrazine on Caiman latirostris thyroid gland are organizational and sexually dimorphic.

GALOPPO, G.H.; MUÑOZ-DE-TORO, M.; LUQUE, E.H.; TAVALIERI, Y.E.

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias 2019; 2019

Sociedad Argentina de Biología (SAB)

Increasing thyroid disorders, mainly in women, raised the hypothesis that exposure to endocrine disruptor compounds (EDCs) and sex-related factors could influence thyroid disease epidemiology. Exposure to EDCs can cause organizational or activational effects. Caiman latirostris is a crocodilian species highly sensitive to EDCs exposure. Atrazine (ATZ) is an herbicide suspected to cause thyroid disruption. Our aims were to describe thyroid histoarchitecture, to assess sexual dimorphic features and to determine the long term effects of prenatal exposure to ATZ on thyroid gland. Male and female caimans prenatally exposed to vehicle or to 0.2ppm of ATZ were raised, biometric parameters were recorded and, at prepubertal juvenile stage, caimans were sacrificed, thyroid were excised, weighed and processed until paraffin embedding. Thyrosomatic (TI) and condition indexes (CI) were calculated. The percentage of the gland occupied by stroma, epithelium or colloid; follicular hyperplasia, follicular epithelial height (FEH) and expression of ERα and Androgen Receptor (AR) were assessed. ANOVA followed by Tukey or Dunn´s post tests were used. No sexual dimorphism was observed in control caimans. Whereas in those ATZ exposed, sexually dimorphic responses were observed. In ATZ-females CIs were higher than in control while the opposite was observed in males. In females, ATZ exposure caused colloid depletion (p=0.0077), increased FEH (p=0.0261) and TI (p=0.0468). In males, ATZ increased ERα expression (p