There is considerable evidence supporting the role of gonadotrophins and
progesterone on follicular growth and maturation and functional maintenance
of the ovary in the hen. Recently, however, there are ever-expanding list of
factors may be involv
ed in establishing follicular growth and ovulation
currently including germinal disc region, growth factors, macrophages,
plasminogen activator, ornithine decarboxylase, inhibin, activin, follistatin,
relaxine, arginin vasotosin, oxytocin, prostaglandines, vasoactive intestinal
peptide, and their interactions.