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

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

Congreso; Congreso Nacional de Biociencias.; 2017

Caiman latirostris is a reptile with temperature sex determination (TSD). In ovoexposure to xenoestrogens overcomes the effects of temperature (hormonal sexdetermination; HSD). External genitalia (phallus) from TSD- males and females aresimilar in gross anatomy; however, male phallus continues increasing its size ascaiman grows. The aims were to evaluate histo-architecture and hormone receptorstatus in the phallus of juvenile caimans to describe the sexual dimorphic patternand to determine whether the phallus of HSD-female caimans differs from thephallus of TSD-females. Archived paraffin embedded samples from juvenilecaimans were used. Groups were as follow: TSD-male, TSD-female and HSDfemale (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 arecomposed by a collagen rich corpus cavernosum (CC), surrounding a vascularizedsmooth muscle tissue, where a ventral invagination of the external epithelium(sulcus) is anchored to. PAS+ staining cells were present in the deep sulcus and inthe external epithelia; muscle cells exhibited cytoplasmic PAS+ granules. Sexualdimorphism was exhibited by: 1) collagen fiber organization in the CC that isdensely packed in males versus loosely packed in females, 2) the spatialorientation of muscle fibers 3) peripheral innervations is higher in females than inmales, and 4) AR and ER expression are both higher in males than in females.Results demonstrate that, sexual dimorphism of caiman phallus is not onlyrestricted to its growing dynamics, but also to histological features and hormonedependency. Aditionally, HSD-female phallus differs from TSD-females.Significant, AR and ERα expression in TSD-female phallus resembles thatobserved in TSD-males. Masculine features of external genitalia from HSDfemales could alter their reproductive behavior and/or performance.