Research on the Concentration of Plasma Testosterone in Silver Foxes (Vulpes fulva) and Polar Foxes (Alopex lagopus) Raised in Captivity

The plasma testosterone determinations were performed on 19 silver fox males (Vulpes fulva) and 19 polar fox males (Alopex lagopus) that were coming from the farm. The concentration of testosterone was performed on prepubertal males (0-10 months), during the sexual period and the period of sexual rest. For quantitative determination of the testosterone, some systems were used like the VITROS system ECi/ECi O2, the immunological diagnostic system VITROS 3600 and the integrated system VITROS 5600. In both species, the plasma concentration was maximal at the males in the period of sexual activity (1.56±0.23 ng/ml at the polar fox and 1.46±0.23ng/ml at the silver fox) and minimal in males between the age 0-10 months (0.22±0.01 ng / ml at the polar foxes and 0.20±0.01 ng/ml at the silver foxes).The adult males that were in the sexual rest period showed low testosterone levels (0.25±0.02 ng/ml at the polar foxes and 0.22±0.02 ng/ml at the silver foxes).