| Summary: | Little is known about polar bears endocrine profile since existing data focused primarly on sun (Ursus malayanus) and Formosan bear (Ursus thibetanus formosanus). This research aims at evaluating sexual profile in two captive pubertal polar bears by the monitoring of progesterone, estradiol and testosterone in fecal samples. Faeces were collected from one male and one female and stored frozen until analysis. Hormone extraction was performed on 0.3 g homogenized faeces with a double ethanol extraction and analyzed with commercial RIA kits for progesterone (P4), estradiol (E2) and testosterone (T). Progesterone was also measured using commercial ELISA kits. RIA and ELISA gave comparable data with p<0.05. The female confirmed to have higher concentration of fecal progesterone compared to the male. Progesterone showed a seasonal fluctuation in both sexes with peak in March, lower levels during the April to early June period and then increasing levels from June onwards. Male testosterone concentrations resulted higher than female’s one (31.36 ± 17.26 pg/mg vs 25.33 ± 52.31 pg/mg respectively), while male estradiol concentrations was observed to have lower values compared to female (4.64 ± 2.81 pg/mg vs 6.05 ± 6.61 pg/mg respectively). Male testosterone presented seasonal fluctuation with increasing and peaking values around April and May. These results strongly suggest that faeces can be used as tool for monitoring sexual profile in polar bears.
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