Meeting Abstract

P1.224  Friday, Jan. 4  Influence of maternal yolk testosterone on aromatase activity in the pre-optic area of the brain in 3-day-old domestic chickens MCAVOY, K.A.*; BENOWITZ-FREDERICKS, Z.M.; Bucknell University, Lewisburg, PA; Bucknell University, Lewisburg, PA kam048@bucknell.edu

Maternal effects are a mother’s non-genetic contributions to development, such as the deposition of androgens into avian egg yolks, that alter many phenotypic traits in offspring. For example, elevated yolk testosterone increases male sexual behaviors such as copulations and courtship displays in some species. However, the mechanism connecting in ovo testosterone exposure with increased sexual behaviors has yet to be elucidated. While testosterone released by the gonads is important in the activation of avian sexual behaviors, it must undergo conversion to estrogen by the enzyme aromatase in the pre-optic area (POA) of the brain for full expression of sexual activity. We hypothesize that the mechanistic link between yolk testosterone and frequency of sexual behavior lies in changes in aromatase activity in the POA. We investigated the effect of elevated yolk testosterone on aromatase activity in the POA of 3-day-old domestic chickens (Gallus gallus domesticus). Unincubated eggs were injected with either 10 ng testosterone in 50 &muL sesame oil (“T chicks”) or 50 &muL sesame oil (“C chicks”). At 3 days post-hatch, the aromatase activity in the POA was quantified by measuring production of tritiated water from [1&beta-³H]-androstenedione. We predicted that aromatase activity would be higher in the brains of T chicks, however found no difference between treatments. Though juvenile T production peaks at 3 days post-hatch, it’s possible that the POA and its aromatase activity are not fully developed at this time.