Epidermal growth factor (EGF) in the quail ovary.

Using immunocytochemical techniques for the localization of epidermal growth factor (EGF) in the quail ovary, we observed a major amount of EGF in smooth muscle cells of blood vessels and of chordae, in interstitial cells, in granulosa cells of small follicles, in the Balbiani complex of prelampbrush oocytes, in nerve cells, and in the cells of granulosa and theca externa of postovulatory follicles. In general, the staining intensity of granulosa cells decreased during folliculogenesis, and increased after ovulation. In the oocyte, immunoreactivity was shifted from the Balbiani complex to the zona radiata during development. These results support the hypothesis that EGF primarily acts on less differentiated follicles. It is also suggested that EGF can modulate ovarian contractile processes.