1. β-Adrenergic responsiveness may be decreased in cystic fibrosis. In order to determine whether this reflects an alteration in the human lymphocyte β-receptor complex, we studied 12 subjects with cystic fibrosis (six were stable and ambulatory and six were decompensated, hospitalized) as compared with 12 normal controls.
2. Lymphocyte β-receptor mediated adenylate cyclase activity (EC 18.104.22.168) was not decreased in the ambulatory cystic fibrosis patients as compared with controls. In contrast, decompensated hospitalized cystic fibrosis patients demonstrated a significant reduction in β-receptor mediated lymphocyte adenylate cyclase activity expressed as the relative increase over basal levels stimulated by the β-agonist isoprenaline compared with both normal controls and stable ambulatory cystic fibrosis patients (control 58 ± 4%; ambulatory cystic fibrosis patients 51 ± 7%; decompensated hospitalized cystic fibrosis patients 28 ± 5%; P < 0.05).
3. Our data suggest that defects in lymphocyte β-receptor properties in cystic fibrosis patients may be better correlated with clinical status than with presence or absence of the disease state.