Ann O. Cheek This is Me

 Web References

1. 1. PCHE Weekly Bulletin

   www.partnersforchildren.org/bu - [Cached]

   Published on: 8/16/2006   Last Visited: 4/10/2007

   All the changes observed suggest that perchlorate "is acting like an androgen," or male-sex hormone, notes fish physiologist Ann Cheek of the University of Texas Health Science Center at Houston.

2. 2. Macho Moms: Perchlorate pollutant masculinizes fish: Science News Online, Aug. 12, 2006

   www.sciencenews.org/articles/2 - [Cached]

   Published on: 8/11/2006   Last Visited: 8/11/2006

   All the changes observed suggest that perchlorate "is acting like an androgen," or male-sex hormone, notes fish physiologist Ann Cheek of the University of Texas Health Science Center at Houston.
   ...
   Ann Cheek University of Texas Health Science Center, Houston

3. 3. Choked Up: How dead zones affect fish reproduction: Science News Online, Nov. 13, 2004

   www.sciencenews.org/articles/2 - [Cached]

   Published on: 11/13/2004   Last Visited: 3/15/2005

   Although the fish were similar in size in the three bays, testes in fish exposed to daily, transient hypoxia were only 34 to 50 percent as large, relative to body size, as those in males living where oxygen is always adequate, notes team leader Ann O. Cheek of the University of Texas Health Science Center at Houston. Ovaries in females exposed to daily hypoxia were only half as big and contained only one-seventh as many eggs as those in females getting sufficient oxygen all day. Fish at hypoxic sites also spawned on only half as many days as the other fish did.
   
   In the wild, hypoxia didn't affect concentrations of sex hormones. In monthlong lab studies with killifish, by contrast, constant hypoxia roughly halved hormone concentrations, Cheek says.
   ...
   Ann O. Cheek University of Texas, Houston Health Science Center 1200 Herman Pressler Drive Houston, TX 77030