Further studies on the anti-inflammatory effect of insulin

Experiments performed on rats showed that insulin, when applied i.v. or s.c., inhibited the foot edema induced by carrageenin, thermic effect of 45.7 degrees C, compound 48/80 and 5-HT, but moderately increased the paw swelling evoked by kallikrein, a kinin-forming enzyme. The increased vascular permeability elicited by intradermal injection of histamine, 5-HT, bradykinin, PGE1, carrageenin and compound 48/80 was also suppressed. The anti-inflammatory effect was not significantly altered by propranolol and adrenalectomy on the thermal and carrageenin edema, it was variably inhibited on the skin test, and was completely abolished on the paw swelling induced by 5-HT and compound 48/80. Since insulin had little or no effect on the vascular response when given topically together with the vasoactive agents, its complex effect on the acute inflammation appears to be brought about via indirect mechanisms.