Radioimmunological evidence for early functional activity in chick embryonic alpha cells.

A radioimmunoassay for glucagon was utilized to investigate early developmental aspects of glucagon synthesis and release in the chick embryo. Immunoreactive glucagon was detected in both the pancreas and blood plasma from the fifth embryonic day onwards. The present data show that the chick embryonic alpha cell has the potential for secretory activity very early in development, and suggest a developmental role for glucagon in hepatic glycogen metabolism.