Tracy Henriques, a graduate student in the laboratories of Drs. Lisa Cassis and Alan Daugherty, presented the study Monday, April 4, at the American Society for Investigative Pathology scientific sessions at Experimental Biology 2005 in San Diego.
In a well-established research method, giving hyperlipidemic mice the peptide hormone angiotensin II results in the development of abdominal aortic aneurysms. Not surprisingly, considering the gender differences in humans, male mice have a three-fold higher susceptibility to developing the angiotensin-induced aneurysms than age-matched females receiving the same drug. Recent studies in the Cassis/Daugherty laboratories revealed that removing the male sex hormones reduced the incidence of aneurysms in male mice to the same lower levels seen in the females.
In this new study, the researchers found that giving male sex hormones to female mice at the time of the angiotensin infusion turns the females into males in terms of their susceptibility. Administration of testosterone raised the incidence of developing abdominal aortic aneurysms by 55 percent in the females; dihydrotestosterone raised the incidence to 67 percent. In addition, the females given male sex hormones developed more severe aneurysms compared to placebo treated female mice.
The goal of the laboratory now is to find the target of the male sex hormones t
Contact: Sarah Goodwin
Federation of American Societies for Experimental Biology