Possible Interaction: Secretin and Theophylline

“The effects of secretin , a proposed ductular stimulant, are potentiated by theophylline.”

“ Theophylline significantly increased bile volume and bile electrolyte changes at all doses of secretin , including maximal doses.”

“Incubation of rat brain frontal cortex slices with secretin or the structurally related peptides peptide histidine leucine (PHI) or vasoactive intestinal polypeptide (VIP) in the presence of 10 mM theophylline resulted in a dose‐dependent increase in the cyclic AMP levels.”

“Almost maximal increase in cellular cyclic AMP levels and 32P incorporation into selected proteins was also observed with 10(-7)M secretin by 10 min in the presence of 10 mM theophyllin.”

“1) At relatively low concentrations (0.1-1.0 mM), theophylline augmented the increase in enzyme secretion caused by vasoactive intestinal peptide, secretin , or 8-bromoadenosine 3',5'-monophosphate, but did not alter the increase in amylase release caused by other secretagogues.”

“A subthreshold concentration of theophylline (2 mM) increased the submaximal responses to VIP or secretin up to but not beyond the maximal response to VIP alone (4.1 ± 0.2 μl mg-1 30 min-1).”

“Addition of 3-10(-7) M secretin to slices incubated in the presence of 10(-2) M theophylline causes 84% increase of the cyclic AMP level above control, whereas the addition of 3-10(-7) M pancreozymin-C-octapeptide has no significant effect.”

“Theophylline alone displayed a large hydrelatic stimulatory effect, without increasing protein excretion; the effect of theophylline was additive with the effects of isoproterenol or secretin but no evidence was found of potentiation or prolongation of action.”

“Replacement of secretin by dibutyryl cyclic AMP and theophylline led to an inhibition of 15%.”