Effect of Fasting, Glucose, Amino Acids and Food Intake on In Vivo Insulin Release in the Chicken

Abstract

Insulin release was studied in vivo in the chicken using the radioimmunoassay previously described (Simon, Freychet and Rosselin 1974). An orally administered glucose load (2g/kg b.w.) stimulated insulin release and was rapidly metabolized. A prolonged fasting period (65 hr) increased both initial plasma glucose and initial plasma insulin levels and highly impaired the glucose tolerance. A fasting-impaired insulin release and/or a fasting tissue "insulin resistance" accounted for this fasting-impaired glucose tolerance. An orally administered amino acid mixture (1g/kg b.w.) stimulated insulin release to a very low extent. The effect was however sufficient to decrease the plasma glucose level. In combination with glucose, the oral amino acid load potentiated the effect of a dose of glucose on insulin release and highly improved the glucose tolerance. This synergism was still observed with the intake of a mixed and balanced diet. Therefore, except for some characteristics observed in the chicken which are discussed, the insulin regulation and the pancreatic β-cell function are qualitatively similar in the chicken and in mammals.