Some Aspects of the Pharmacology of Diphenyleneiodonium, a Bivalent Iodine Compound

Abstract

1. Previous studies have established that diphenyleneiodonium binds to and inhibits the respiratory enzyme NADH dehydrogenase and also catalyses an exchange of Cl⁻ for OH⁻ across membranes.

2. The hypoglycaemia produced by diphenyleneiodonium was confirmed and shown to be reversible at a dose of 4mg/kg in starved rats.

3. The lethality of diphenyleneiodonium in mice was cumulative.

4. Presumably as a result of the Cl⁻/OH⁻ exchange, diphenyleneiodomum-treated rats excreted less Cl⁻ than controls in the first 12 h after administration. However, the swelling of erythrocytes observed in vitro did not occur in vivo.

5. When [¹²⁵I]diphenyleneiodonium was administered to rats and rabbits, its distribution did not appear to be governed by its binding to NADH dehydrogenase. Reasons for this are discussed.

6. Over 90% of the radioactivity excreted in the faeces of rabbits could not be extracted with boiling water or with dil. HNO₃.