06 - The movement and metabolism of Corticosterone in fertile and unfertile Japanese quail (Coturnix japonica)
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 a class of hormone steroids 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 quail eggs. Both fertile and infertile eggs were injected with [H3]-cort into the yolk and allowed to develop for 3, 6, 9, 12, or 15 days. After development, eggs from each experiment were separated into albumen, yolk, and embryonic portions and the radioactivity within each portion was characterized. Results showed that embryonic factors modulate the maternally derived prenatal environment. Unexpectedly, the 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.