Neutrophils from drug-free elderly subjects produced approximately 50% less cyclic AMP in response to isoprenaline than did neutrophils from young subjects. A significant difference in basal cyclic AMP levels was also evident (elderly 2.8 +/- 0.37; young 4.9 +/- 0.36 pmol of cAMP/10(7) cells; P less than 0.05). With a range of anti-neutrophil monoclonal antibodies no evidence of age-related neutrophil population heterogeneity was found. These findings indicate that the age-related decline in beta-adrenoceptor responsiveness is not due to changes in the neutrophil population. The present results support the hypothesis that there is a generalized decline in beta-adrenoceptor-mediated responsiveness in the elderly.