P1.129 Saturday, Jan. 4 15:30 In ovo movement and metabolism of corticosterone throughout avian development VASSALLO, BG*; FASANELLO, VJ; PAITZ, RT; HAUSSMANN, MF; Bucknell Univ, Lewisburg; Bucknell Univ, Lewisburg; Univ Illinois, Urbana; Bucknell Univ, Lewisburg email@example.com
Maternal effects are a parental method of prenatally fine-tuning offspring for current, local environmental conditions, alternative to genetic inheritance. Accordingly, a parent’s physiological state can affect the physiological condition and life trajectory of their offspring. Glucocorticoids (GCs) are steroid hormones, implicated in a number of maternal effects, which function in metabolic homeostasis, as well as an animal’s response to stressful conditions. The mechanism by which GC-induced maternal effects proceed is still relatively unknown. Here we tracked the movement and metabolism of corticosterone (cort; the main avian GC) in developing Japanese quail eggs (Coturnix japonica). To first test the importance of injection site (yolk vs. albumen), fertilized eggs were injected into the yolk or albumen with [H3]-cort and allowed to develop for 5 d. In the second experiment both fertile and unfertile eggs were injected into the yolk with [H3]-cort and allowed to develop for 3, 6, 9, 12, or 15 d. After development, eggs from each experiment were separated into albumen, yolk, and embryonic portions and the radioactivity within each portion was characterized. Results from the first experiment indicate that distribution of [H3]-cort depends on site of injection. The second experiment clearly showed that embryonic factors modulate the maternally derived prenatal environment. Unexpectedly, cort injected into the yolk did not remain in its original form, but was conjugated over the course of development. While less than 20% of the [H3]-cort entered the embryo, the majority of this was also found in a conjugated form, indicating that in metabolizing cort the embryo may be playing an active role in altering potential maternal effects.