title: Structure-activity relationship study of the inhibition of adrenal cortical 11 beta-hydroxylase by new metyrapone analogues.
abstract: Metyrapone, 2-methyl-1,2-di-3-pyridyl-1-propanone (1a), is a potent reversible inhibitor of the cytochrome P-450 11 beta-hydroxylase enzyme system (P-450(11) beta) of the adrenal cortex. The structural features of the metyrapone molecule have been systemically altered to determine the requirements necessary for inhibition of P-450(11) beta activity. Metyrapone and 14 analogues have been obtained or synthesized and evaluated as inhibitors using a crude, defatted bovine adrenal cortical mitochondrial preparation. The inhibition of P-450(11) beta activity with these derivatives demonstrated that (1) the A-ring phenyl derivatives 2a-d were better inhibitors than the respective dipyridyl analogues, (2) the ketone in the 1-position can be replaced by various functionalities without markedly reducing inhibition, and (3) at least one methyl group should be present in the 2-position to maintain inhibition. The observed inhibition of P450(11) beta activity with the metyrapone analogues suggest that A-ring phenyl metyrapone analogues 2a-d would be candidates for radioiodination and subsequently used as adrenal cortical imaging agents.
mesh_terms: D000302:Adrenal Cortex / Q000201:enzymology*; D000818:Animals; D002417:Cattle; D003577:Cytochrome P-450 Enzyme System; D007202:Indicators and Reagents; D007700:Kinetics; D008797:Metyrapone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008928:Mitochondria / Q000201:enzymology*; D013252:Steroid 11-beta-Hydroxylase / Q000037:antagonists & inhibitors*; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
chemical_list: D007202:Indicators and Reagents; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D013252:Steroid 11-beta-Hydroxylase; D008797:Metyrapone