COMENIUS UNIVERSITY RESEARCH: FEMALE ANIMALS ARE LESS ANXIOUS THAN MALE ANIMALS
Female are less full of anxiety than males. This is a valid observation for animals in early maturity as well as those in old age. This was a conclusion that was reached by research performed on rats by Comenius University doctoral student Emese Domonkos from the Institute of Molecular Biomedicine at Comenius University’s Faculty of Medicine.
The link between circulating sexual hormones and the occurrence of affective disorders has been described in both men and women. The higher occurrence of anxiety and depressive states among women, and the growing occurrence of these disorders in men as they get older are indicative of the role of sexual hormones in the aetiology of affective disorders. However, the causal relationship between the concentration of sexual hormones and the degree of anxiety is not clear.
“In contrast to humans, it was shown that female animals are actually less anxious than male animals. These sexual differences in anxious behaviour were exhibited in animals in early maturity as well as in old age,” said Emese Domonkos in discussing her research. Ageing in men and male animals is connected with the progressive reduction of circulating testosterone (hypogonadism). In humans, it is assumed that hypogonadism connected with age is responsible for some symptoms of ageing, such as a cognitive reduction and affective disorders. “Experiments on animals confirmed that older males presented a greater degree of depression and anxiety than those who were younger. Until now, it has not been clear to what degree the sexual differences among older specimens in affective behaviour are influenced by the endogenic production of sexual hormones,” said Domonkos.
The short-term effects of hypogonadism on behaviour have been described in several published studies. It also appears that age is an important factor which modulates the effect of hypogonadism. It increases anxiety in mature male animals, whereas in the early stages of development, it lowers anxiety. “The influence of long-term hypogonadism on the anxious behaviour of ageing males has not yet been adequately studied. Our study is unique in that it examines the influence of the life-long deficit of sexual hormones on anxious behaviour. We confirmed the published information on sexual differences in anxious behaviour and we showed that to a certain degree this is caused by the internal production of androgens,” said Domonkos.
Domonkos’s nearly two-year-long experiment, under the guidance of Dr Július Hodosy and Associate Professor Peter Celec, has been aided by the participation of fellow doctoral student Veronika Borbélyová.