Effects of social stress on behavior and corpus luteum in female golden hamsters (Mesocricetus auratus).
The consequences of group-keeping as a social stressor on the solitary-living golden hamster were studied. Two females at the same stage of the estrous cycle were kept together for 5 weeks. Behavioral observations showed that the dominance structures within groups were unstable. Intensity of aggression was highest at metestrous, whereas the greatest activity was observed during the estrous stage. After 1 week, the body masses of singly kept and group-kept hamsters were different. Five weeks after the onset of the experiment, the body mass of the singly kept hamsters had increased by 3.6%, and that of the group-kept hamsters by 25%. The plasma progesterone level of group-kept females was 60 to 70% higher than that of singly kept females. The absolute masses of the adrenal glands and the ovaries were higher in group-kept females. Nevertheless, the relative masses did not differ. Whereas a significant positive correlation between the weights of both organs and the body mass was observed in singly kept females, in group-kept females such a correlation was only observed between body and ovary weight. Number and size of corpora lutea were enlarged in group-kept individuals, and this seems to be responsible for elevated plasma progesterone titres. These results indicate social stress in group-kept female hamsters.
Fritzsche
P
P
Institute of Zoology, Martin-Luther-Universität Halle-Wittenberg, Domplatz 4, 06108, Halle, Germany. fritzsche@zoologie.uni-halle.de
Riek
M
M
Gattermann
R
R
D000311:Adrenal Glands / Q000254:growth & development / Q000502:physiology; D000374:Aggression / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D003338:Corpus Luteum / Q000254:growth & development / Q000502:physiology*; D006224:Cricetinae; D004971:Estrus / Q000502:physiology*; D005260:Female; D008647:Mesocricetus; D009929:Organ Size / Q000502:physiology; D011374:Progesterone / Q000097:blood*; D012930:Social Dominance; D018709:Statistics, Nonparametric; D013315:Stress, Psychological / Q000503:physiopathology*; D014743:Videotape Recording
D011374:Progesterone