Association of increased polyamine levels with isoproterenol-stimulated mucin secretion in the rat submandibular gland.

Incubation of rat submandibular gland slices with 50 microM isoproterenol for 10-40 min stimulated mucin secretion and induced a 3- to 4-fold increase in tissue concentrations of the polyamines putrescine, spermidine and spermine. alpha-Difluoromethylornithine, a specific inhibitor of ornithine decarboxylase, suppressed the isoproterenol-induced increase in submandibular polyamines and inhibited mucin secretion. Exogenous putrescine restored tissue polyamine levels and partially reversed the inhibitory effect of alpha-difluoromethylornithine on mucin secretion. Rapid increases in polyamine levels appear to mediate isoproterenol-stimulated mucin secretion in the rat submandibular gland.