Serum myoglobin concentrations are decreased by beta-adrenergic stimulation

During infusion with adrenaline in healthy subjects there was a more than 50% reduction in serum myoglobin concentrations. This effect appeared to be specific for beta-adrenergic stimulation, since no changes were seen after prior IV beta-blockade with propranolol, nor did noradrenaline affect the serum myoglobin levels. Oral beta-blockade with propranolol raised the basal serum levels of myoglobin and enhanced the exercise-related rise in serum myoglobin concentrations during ergometer cycling to exhaustion. These observations thus indicate that the beta-adrenergic system affects serum myoglobin concentrations. This should be kept in mind in the evaluation of myoglobin measurements for clinical purposes, and might reflect a physiologically relevant mechanism.