External genitalia from juvenile Caiman latirostris. Similarities and differences between male, TSDfemales and HSD-females.

LUQUE, ENRIQUE H.; TAVALIERI, YAMIL E.; CANESINI, GUILLERMINA; MUÑOZ-DE-TORO, MÓNICA M.; GALOPPO, GERMÁN H.; LUQUE, ENRIQUE H.; TAVALIERI, YAMIL E.; CANESINI, GUILLERMINA; MUÑOZ-DE-TORO, MÓNICA M.; GALOPPO, GERMÁN H.

MONTEVIDEO

Congreso; CONGRESO NACIONAL DE BIOCIENCIAS 2017; 2017

SOCIEDAD URUGUAYA DE BIOCIENCIAS

Caiman latirostris is a reptile with temperature sex determination (TSD). In ovo exposure to xenoestrogens overcomes the effects of temperature (hormonal sex determination; HSD). External genitalia (phallus) from TSD- males and females are similar in gross anatomy; however, male phallus continues increasing its size as caiman grows. The aims were to evaluate histoarchitecture and hormone receptor status in the phallus of juvenile caimans to describe the sexual dimorphic pattern and to determine whether the phallus of HSD-female caimans differs from the phallus of TSD-females. Archived paraffin embedded samples from juvenile caimans were used. Groups were as follow: TSD-male, TSD-female and HSD female (incubated at male producing TºC and exposed in ovo to 1.4 ppm of 17β Estradiol). From the base to the glans, external genitalia of male and female are composed by a collagen rich corpus cavernosum (CC), surrounding a vascularized smooth muscle tissue, where a ventral invagination of the external epithelium (sulcus) is anchored to. PAS+ staining cells were present in the deep sulcus and in the external epithelia; muscle cells exhibited cytoplasmic PAS+ granules. Sexual dimorphism was exhibited by: 1) collagen fiber organization in the CC that is densely packed in males versus loosely packed in females, 2) the spatial orientation of muscle fibers 3) peripheral innervations is higher in females than in males, and 4) AR and ER expression are both higher in males than in females. Results demonstrate that, sexual dimorphism of caiman phallus is not only restricted to its growing dynamics, but also to histological features and hormone dependency. Aditionally, HSD-female phallus differs from TSD-females. Significant, AR and ERα expression in TSD-female phallus resembles that observed in TSD-males. Masculine features of external genitalia from HSD-females could alter their reproductive behavior and/or performance.