REDUCED MATING BEHAVIOR IN ESTROGEN EXPOSED XENOPUS LAEVIS MALES
Alejandra Cabrera, Tyrone Hayes, Flor Gowans, Cara He, Faye Pon, Diana Salazar, Karen Jiawen Zhang, Maggie Tsang, Mai Nguyen, Xuan (Susan) Luong, Sherrie Gallipeau.
University of California, Berkeley, Berkeley, CA.
Atrazine reduces testosterone (T) and increases estradiol (E2) production in male African clawed frogs (Xenopus laevis). Atrazine also inhibits male reproductive behavior. In the current study, we examined whether the loss of male mating behavior was due to increased E2 and/or decreased T, and assessed whether E2 inhibited male reproductive behavior by decreasing endogenous T. Immersion in E2 or 17α-ethinyl estradiol (EE2) and E2 implants were used to elevate estrogen levels and examine effects on male reproductive behavior. E2-treatment by immersion was ineffective. T levels in treated males were reduced dramatically 24 hours after exposure but shortly returned to normal. Treatment with EE2, which has a longer half-life, reduced male reproductive behavior. Males treated with EE2 were out-competed by control males 3 to 1. E2 implants also reduced male reproductive behavior. Control males out-competed treated males 11 to 2. E2 levels ranged from 13 - 42 ng/ml in implanted males, but T levels were not affected in an earlier study, and current analysis will determine hormone levels in animals used in breeding studies. Both E2 and EE2 decreased reproductive behavior, but possibly independent of any effects on endogenous T.