Plasmatic estradiol and progesterone variations during the reproductive cycle of captive female argentine red tegu lizards, tupinambis rufescens

Abstract

We analyzed the plasmatic profiles of 17 β-estradiol and progesterone during the reproductive cycles of captive female Argentine Red Tegu lizards (Tupinambis rufescens). We studied adult females, some of which oviposited and subsequently incubated their eggs (fertile females), and some of which did not oviposit and, therefore, did not incubate (infertile females). Regardless of oviposition status, circulating levels of 17 β-estradiol were elevated at the end of hibernation, then diminished gradually and reached the minimum level in the pre-ovulatory stage. After oviposition, hormonal levels increased, reached their peak during incubation, and stayed elevated throughout reproductive quiescence. Progesterone showed the reverse pattern to 17 β-estradiol, increasing progressively from the end of hibernation to reach maximum concentration during the pre-ovulatory phase, at which point it started to decrease. We also found higher values of 17 β-estradiol and progesterone in incubating females compared with those that did not incubate. These results suggest a possible association between hormonal cycles and maternal behavior in this species, although the small sample size limits our ability to draw conclusions.