Proof that Sn-protoporphyrin inhibits the enzymatic catabolism of heme in vivo. Suppression of 14CO generation from radiolabeled endogenous and exogenous heme sources.
Sn-protoporphyrin (SnPP) suppresses generation of 14CO from hepatic heme labeled with delta-aminolevulinic acid (5-[14C]ALA) or from infused [14C]hemin in rats. SnPP administered 1 h before administration of 5-[14C]ALA virtually abolished the peak output of 14CO occurring 2-3 h after injection of this heme precursor, and during the succeeding 12 h reduced 14CO excretion by approximately 61% compared with controls. When [14C]hemin was infused, SnPP diminished 14CO excretion by approximately 50%. These findings, derived from experiments using radiolabeled endogenous and exogenous heme sources, establish conclusively that the synthetic metalloporphyrin SnPP inhibits the oxidative degradation of heme in the intact animal.
D000622:Aminolevulinic Acid / Q000378:metabolism; D000818:Animals; D002248:Carbon Monoxide / Q000096:biosynthesis; D006418:Heme / Q000378:metabolism*; D006427:Hemin / Q000378:metabolism; D008665:Metalloporphyrins; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D008665:Metalloporphyrins; D011166:Porphyrins; D011524:Protoporphyrins; D006418:Heme; D006427:Hemin; D002248:Carbon Monoxide; D000622:Aminolevulinic Acid; C032628:tin protoporphyrin IX