The effects of acute release of endogenous catecholamines on both platelet alpha 2 and leukocyte beta adrenoreceptors and metabolic indices (glucose and free fatty acids) were investigated in dogs by means of a model of neurogenic hypertension following acute sinoaortic denervation (ASAD). Despite the marked increase in catecholamine levels (+4.2-fold for noradrenaline and 16.7-fold for adrenaline, for example, at minute 45 following ASAD) and in glucose plasma levels, and the significant decrease in free fatty acid plasma levels, no change in platelet alpha 2 or leukocyte beta adrenoreceptor binding sites (number as well as affinity) was observed during the whole experiment. It is suggested that the number of platelet alpha 2- and leukocyte beta-adrenoreceptors is not submitted to short-term regulation, at least by endogenous catecholamines in dogs.