TESTOSTERONE IS CLOSELY RELATED TO LEYDIG CELL ACTIVITY, ANDROGEN RECEPTOR DISTRIBUTION AND ENVIRONMENTAL FACTORS IN ADULT MALE LIZARDS OF LIOLAEMUS CUYANUS DURING THE REPRODUCTIVE CYCLE

BARAUNA A; CONTE, MARÍA INÉS; LEPORATI, JORGE LEANDRO; QUIROGA, L.; SANABRIA, E. A.; FORNÉS M.

Congreso; Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2023

SBC

Testosterone, the primary sex hormone in male lizards, is closely linked to Leydig cell (LC) activity (the cells where steroidogenesis occurs)throughout the reproductive cycle, but testosterone action is related to androgen receptors (ARs) distribution in the seminiferous epithelium.In temperate zones, environmental factors detected through the hypothalamic-pituitary-gonadal axis, down-regulate serum testosterone,resulting in a seasonal reproductive cycle. The aim of this work is to study the serum testosterone in adult male lizards of Liolaemus cuyanus,an oviparous species, throughout its reproductive cycle and its relationship with Leydig cell histology, the ratio of TotalLC / ActiveLC, ARsdistribution in the seminiferous epithelium and the regulation by environmental factors (temperature, relative humidity and solar irradiation).Specimens (N=27) were captured (October to March) in a semi-arid zone (Valle de Matagusanos, San Juan, Argentina; -31°06’46.08’’S,68°38’03.84’’W) and grouped into three relevant reproductive periods: pre-reproductive (PrR), reproductive (R) and post-reproductive (PsR).Significant differences in serum testosterone were found among these periods, highest during the R period, with a decrease in PsR. Significantpositive correlation between serum testosterone and the ratio of TotalLC / ActiveLC was also observed. In PrR and R, ARs distribution wascytoplasmic and nuclear, shifting to only cytoplasmic in the PsR period. Serum testosterone has a significant positive correlation only withsolar irradiation. However, solar irradiation has a significant positive correlation with temperature. These results highlight the closecorrespondence between serum testosterone, Leydig cell histology and activity, ARs distribution in the seminiferous ephitelium andenvironmental factors, resulting in a synchronization that allows males of L. cuyanus to coordinate their reproductive cycle with the mostfavorable environmental conditions, probably for mating and birth of offspring