Effect of serum from normal and cystic fibrosis subjects on mucin secretion from dispersed rat submandibular cells

The action of serum from cystic fibrosis patients, obligatory heterozygotes, siblings, and normal patients on mucin secretion from dispersed rat submandibular cells was investigated in an attempt to demonstrate the existence of cystic fibrosis specific factors affecting mucin secretion. No effects specific to cystic fibrosis serum were demonstrated using the following parameters for evaluation: (1) maximal stimulation of mucin release by a β-adrenergic agonist, (-)-isoproterenol; (2) basal release (unstimulated secretion) of mucin material; and (3) the dose-receptor relationship for mucin release after β-adrenergic receptor stimulation. No differences were observed in mucin secretion using media concentrations of serum of up to 10%. From these data, we conclude that serum from individuals with cystic fibrosis does not contain bioactive factors at concentrations that specifically alter mucin secretion in rat submandibular acinar cells.