Vaginal citology, serum estradiol and progesterone: a correlation study on captive African lions (Panthera leo)

Abstract

Eleven captive adult female African lions (Panthera leo) at the Fundação Parque Zoológico de São Paulo were blood sampled in order to assess the serum hormone levels (estradiol and progesterone) and their correlation with the vaginal citology. The morphological and stainning characteristics of vaginal cells were similar to those described for domestic cats. Based on hormonal profiles of estradiol and progesterone described for domestic cats, three different phases for the ovarian cycle of the lionesses were clearly described: diestrus, estrus and interestrus. The mean serum estradiol concentrations in the estrus (23,33 +/- 2,92 pg/ml) were significantly higher than in diestrus and interestrus. The mean serum progesterone values in diestrus (20,12 +/- 17,55 ng/ml) were significantly higher than in estrus and interestrus. There were correlations between progesterone values and the number of superficial cornified vaginal cells (r = - 0,603 and p = 0,0496) and between progesterone and intermediate cells (r = 0,637and p = 0,0350). There were also a strong negative correlation between the number of superficial cornified vaginal cells and intermediate cells (r = -0,979 e p < 0,0001). It concluded that the correlations between vaginal cells and the serum estradiol and progesterone levels allowed us to identify three different phases of the ovarian cycle in female African lion.