[Pharmacological analysis of the mechanism of action of prodigiozan].

It was shown experimentally on mice that prodigiozan did not increase the acute toxicity of prednisolone. It lowered the prednisolone-induced reduction of the period of hexenal sleep and preserved the capacity for increasing resistance to infection, when the adrenal cortex was blocked with metopiron. These findings together with the literature data were interpreted as arguments against the assumption that glucocorticoid mobilization was an important factor of the prodigiozan mode of action. Blocking of the beta-adrenoreceptors with obsidan increased the capacity of prodigiozan to activate the macrophage system and to raise the nonspecific resistance to infection, while blocking of the alpha-adrenoreceptors with phenolphthalein lowered this capacity. It was suggested that the macrophage activation was mediated by the alpha-adrenoreceptors and was due to a decrease in the cAMP/cGMP ratio.