Molecular Pharmacology, Vol 5, 499-506, Copyright © 1969 by the American Society for Pharmacology and Experimental Therapeutics

Biphasic Decrease of Radioactive Hemoprotein from Liver Microsomal Carbon Monoxide-Binding Particles

Effect of Phenobarbital and Chlordane

¹ The Wellcome Research Laboratories, Burroughs Wellcome & Company, Inc., Tuckahoe, New York 10707

The administration of -aminolevulinic acid-3,5-³H to immature male rats leads to the incorporation of radioactivity into hemoprotein in the CO-binding particles. The incorporated radioactivity decreases in two distinct phases: a rapid phase with a half-life of 7-8 hr and a slow phase with a half-life of 46-48 hr. Treatment with phenobarbital or chlordane does not appreciably after the ratio of the fast-phase component to the slow-phase component but does increase the half-life to the fast phase of 11-12 hr. The increase in the protoheme content of the CO-binding particles found after phenobarbital and chlordane treatment suggests that these compounds increase the amount of both the rapidly and slowly decaying components.