Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 1997
Publication Date: N/A
Interpretive Summary: The insulin-like growth factors, IGF-I and IGF-II, comprise a conserved pair of secreted proteins with diverse effects on growth, development and metabolism. Very little information is available on the role of these peptide hormones in avian species. More is known about the importance of these compounds in mammals than in any other species. Much of what is known about their action in birds has been derived from studies conducted either on cells or tissues derivedfrom birds or from in vivo experiments. Biochemically and physiologically, significant differences in the composition and action of growth factors in birds is different than in other species. This information would be of interest to scientists and the general public.
Insulin-like growth factor-I and -II are important multifunctional polypetides which interact with membrane-bound receptors as well as soluble binding proteins. The biological actions of these hormones are multifaceted, and are dependent to a large extent on binding protein interactions. Some unique differences in insulin-like growth factor physiology and biochemistry are evident between mammalian and avian species. These include amino acid compositional and significant receptor differences as well as binding protein status. The biological response to both growth factors is maybe different in birds. A greater proportion of the insulin-like growth factors exist in plasma as free peptide compared to the situation in mammals. This review is a brief summary of our knowledge on insulin-like growth factor physiology in domestic fowl.