The dextran "anaphylactoid" inflammation in the rat does not occur during alloxan diabetes. It is restored by insulin administration. The inhibition of this inflammation during alloxan diabetes is mainly due to the lack of insulin.

A single subcutaneous injection of crystalline insulin (20 units) sensitizes considerably the rats to the dextran "anaphylactoid" reaction. This is a type of acute serous inflammation. Insulin precipitates the reaction after a very small dose of dextran (0.05–0.01 ml., 6% solution) has been injected into a "shock organ". Without insulin, such small doses of dextran are quite ineffective. Insulin also precipitates the reaction when dextran (1.0 ml., 6% solution) is injected peripherally on the back. In this site and at this dose, it rarely produces the reaction in normal rats. The sensitization manifests itself despite a cortisone pretreatment.

The anaphylactoid reaction produced in donor rats by an intravenous injection of 12 mg of dextran/100 g body wt., can be transferred passively, 60 min later, into acceptor rats, by an intravenous injection of 0.5 ml of the serum from donors. The anaphylactoid reaction resulting in the acceptors is due to a factor, produced in the serum of donors, which is other than the original dextran, histamine, serotonin, or heparin. The production of this factor is potentiated when the rats are presensitized to dextran. It is suggested that the dextran anaphylactoid reaction belongs together with anaphylaxis to the class of immediate hypersensitivities.

Male Sprague-Dawley rats, 120–150 gm in body weight, injected simultaneously with the glucan dextran (1 ml 6% w/v, i.p.) and with an overdose of glucose (3 x 5 ml, 25% w/v, s.c.) which cannot be markedly reduced by excretion in about 24 hours, do not undergo dextran ‘anaphylactoid’ inflammation. If the amount of glucose is smaller (2 x 5 ml, 25% w/v, s.c.) and can be reduced by excretion within about 10 hours, the inflammation occurs, but is greatly delayed in time and diminished in intensity. The specific inhibitory action glucose exerts on the biological activity of the glucan dextran is discussed.