Expressão do fator de crescimento semelhante à insulina I (IGF-I) no músculo peitoral e semimembranoso em duas populações do ganso migratório Branta leucopsis Bechstein (Anseriformes, Anatidae) em diferentes fases de desenvolvimento

de Cássia da S. e Sá, RitaA. B. Mahecha, GérmanEl Haj, AliciaJ. Butler, Pat

Many species of migrating birds travel great distances to reproduce. The process of preparation for migration of young birds involves the development of a muscular-skeletal system capable of sustaining prolonged flights and the alterations underwent by muscle fibres which are under control of factors such as nervous and hormonal stimuli. Considering that insulin-like growth factor I (IGF-I) acts as a mediator of the growth hormone effects, essential for muscular development, in this paper, the IGF-I expression is investigated in the pectoralis and semimembranosus muscles of two populations (wild and captive) of the migratory bird Branta leucopsis. The primary policlonal antibody anti-IGF-I was used for immunocytochemical recognition of epitopes present in muscle fibres in different stages of development. Variations in the pattern ofimmunoreactivity distribution among the phases of development and between the muscles have been hown. Differences regarding the antibody reactivity between wild and captive populations have not been noted.