Article révisé par les pairs
Résumé : The participation of catecholamines in the inhibition of insulin secretion and stimulation of glucagon release during exercise and stress is reviewed. In rats injected with guinea pig anti insulin serum and either compelled to swim or exposed to electric shocks, the rate of insulin secretion is markedly inhibited, mimicking the situation found after administration of exogenous epinephrine. Prior injection of phentolamine abolishes the exercise induced inhibition of insulin release. These findings support the concept that such an inhibition is due to activation of the alpha adrenergic receptors of the beta cell by endogenously released catecholamines. In addition to inhibiting insulin secretion, epinephrine is shown to stimulate glucagon release in vitro, using pieces of pancreas from duct ligated rats incubated at both low and high glucose concentrations. Augmentation of glucagon release is also observed in vivo during exercise or stress. It is concluded that the hormonal regulation under the latter situations is optimally oriented for the mobilization of energetic substrates such as glucose and fatty acids.