Mimickry of anti-granuloma effect of prostaglandin E by dibutyryl cyclic-AMP and some phosphodiesterase inhibitors.

Local administration of PGE1 to pre-formed inflammatory granulomata of rats results in a decrease of granulomatous tissue and reduction of prostaglandin concentrations in granulomatous exudates. Under the same experimental conditions, a similar correlation between these two effects is observed with dibutyryl cyclic-AMP. An anti-granuloma effect is also achieved with the phosphodiesterase inhibitors, IBMX and RA-233, but not with theophylline, a rather feeble inhibitor of this enzyme. The present findings provide further support for the concept that elevation of cyclic-AMP in cell population(s) within granuloma is a promising line for pharmacological suppression of inflammatory tissue proliferation.