New knockout model confirms a role for androgen receptors in regulating anxiety-like behaviors and HPA response in mice.
Men are less likely than women to suffer from anxiety disorders. Because gonadal hormones play a crucial role in many behavioral sex differences, they may underlie sex differences in human anxiety. In rodents, testosterone (T) exerts anxiolytic effects via the androgen receptor (AR): we found that male mice with a naturally-occurring mutation rendering the AR dysfunctional, referred to as spontaneous testicular feminization mutation (sTfm), showed more anxiety-like behaviors than wildtype (WT) males. Here, we used Cre-lox recombination technology to create another dysfunctional allele for AR. These induced Tfm (iTfm) animals also displayed more anxiety-like behaviors than WTs. We further found that AR-modulation of these behaviors interacts with circadian phase. When tested in the resting phase, iTfms appeared more anxious than WTs in the open field, novel object and elevated plus maze tests, but not the light/dark box. However, when tested during the active phase (lights off), iTfms showed more anxiety-related behavior than WTs in all four tests. Finally, we confirmed a role of T acting via AR in regulating HPA axis activity, as WT males with T showed a lower baseline and overall corticosterone response, and a faster return to baseline following mild stress than did WT males without T or iTfms. These findings demonstrate that this recombined AR allele is a valuable model for studying androgenic modulation of anxiety, that the anxiolytic effects of AR in mice are more prominent in the active phase, and that HPA axis modulation by T is AR dependent.
Michigan State University, Psychology Department, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA. Electronic address: chieh.07@gmail.com.
Chieh V
CV
Chen
Michigan State University, Psychology Department, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA.
Jennifer L
JL
Brummet
Michigan State University, Psychology Department, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA; Michigan State University, Neuroscience Program, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA.
Joseph S
JS
Lonstein
Michigan State University, Psychology Department, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA; Michigan State University, Neuroscience Program, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA.
Cynthia L
CL
Jordan
Michigan State University, Psychology Department, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA; Michigan State University, Neuroscience Program, 293 Farm Lane, Giltner Room 108, East Lansing, MI 48824, USA.
S Marc
SM
Breedlove
D013734:Androgen-Insensitivity Syndrome / Q000235:genetics / Q000503:physiopathology; D000818:Animals; D001007:Anxiety / Q000378:metabolism* / Q000503:physiopathology; D001522:Behavior, Animal / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D023421:Models, Animal; D017440:Photoperiod; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology; D013739:Testosterone / Q000502:physiology*
D011944:Receptors, Androgen; D013739:Testosterone; D003345:Corticosterone
Androgen insensitivity; Androgen receptor; Anxiety; Corticosterone; Cre–lox technology; HPA axis; Photoperiod; Testosterone