[Immunological properties and biological activity of chicken glucagon]

A comparative study of avian (chicken) glucagon and commercial preparations of cattle glucagon was carried out with the view of studying the evolution of polypeptide hormones in some vertebrate species. A chromatographic procedure for obtaining crystalline hormone preparations from chicken tissues was developed. Study of immunological properties of chicken glucagon in radioimmune systems with highly specific antisera to mammalian glucagon revealed that the immunoreactivity of chicken hormone preparations purchased from CNR (USA) and RSL (USA) makes up to 40% and 60% of that of mammalian glucagon. Estimation of biological activity of the hormones by their ability to activate adenylate cyclase in a test system with plasma membranes of chicken and rat liver as well as to stimulate lipolysis in a test system with chicken adipocytes revealed that chicken glucagon possesses a biological activity within the same concentration range as its mammalian counterpart, i. e., 2.9 X 10(-10)-1 X 10(-5) M. In the majority of cases the effect of chicken glucagon taken in the above concentrations was less pronounced than that of the mammalian hormone. The data obtained suggest that even one amino acid substitution in the chicken glucagon molecule (in comparison with mammalian glucagon) affects the immunological properties of the hormone and its biological activity.