Med. Weter. 71 (10), 638-642, 2015

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Gorajewska E., Filistowicz A., Nowicki S., Przysiecki P., Filistowicz A.
Physiological level of cortisol and testosterone in the blood of Arctic fox females
The aim of this study was to determine physiological levels of stress hormones (e.g. cortisol and testosterone) in the blood of polar fox females characterized by a specific genotype and karyotype and also the type of behavior. In 2010, an estimation of the type of behavior of all females from a pack based on the type of behavioral response (empathic test, alimentary test, acoustic test) was provided. In the blood of 136 females randomly selected from the fundamental pack, physiological levels of stress hormones (e.g. cortisol and testosterone) were determined. Additionally, the analysis of polymorphism of karyotypes of 72 females in this group was conducted. Heritability and repeatability coefficients in the base levels of cortisol and testosterone in the blood serum was evaluated. The average basal level of cortisol in the blood serum of polar fox females was 46.04±25.86 nmol/l, and testosterone 0.45±0.22 nmol/l. The heritability coefficient of the basal cortisol level stated 0.30±0.11 and testosterone 0.24±0.13; the repeatability coefficient of the basal levels of cortisol was 0.42 and 0.37 of testosterone. The multivariate analysis of variance revealed non-significant differences between the studied groups of animals. Some tendencies were noted explaining the differentiation in hormone levels within particular effects (participation of genes of Finnish variety, karyotype and type of behavior: empathic test, alimentary test and acoustic test). The highest basal levels of cortisol (51.98 nmol/l) and testosterone (0.51 nmol/l) were found in the group of foxes of national breeding. The highest value of cortisol was obtained in the female group of 48 chromosomes (55.20 nmol/l) and lowest in a group of foxes with karyotype 2n=50 (49.06 nmol/l). Studies have shown the highest physiological level of testosterone in the blood of gentle individuals. It was also noted that foxes with a high concentration of this hormone were simultaneously characterized by a low cortisol level.
Key words: artic fox, cortisol, testosterone, stress.