title: A case of deficiency of N-hydroxylation of amobarbital.
abstract: It has been shown recently that the overall metabolism of amobarbital in man is essentially under genetic control. The drug normally undergoes two hydroxylation reactions, leading to 3'-hydroxyamobarbital (C-OH) and N-hydroxyamobarbital (N-OH). This paper describes a sibship in which two mothers who are identical twins show a gross deficiency on N-OH elimination in urine. The whole set of sibship data suggests that this deficiency represents a recessive trait controlled by a single pair of allelic autosomal genes which regulate N-OH formation. Several methodical approaches to assess an individual's capacity for N-OH formation are illustrated. There was no evidence of compensatory or concordant regulation of the two hydroxylation reactions. The case of this family illustrates that the functional lack of a biotransformation reaction is almost certain to be overlooked if one measures only the disappearance of a multimetabolized drug and not the appearance of metabolites.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000654:Amobarbital / Q000378:metabolism* / Q000652:urine; D001711:Biotransformation; D005260:Female; D006207:Half-Life; D006801:Humans; D006900:Hydroxylation; D007700:Kinetics; D008297:Male; D008661:Metabolism, Inborn Errors / Q000235:genetics / Q000378:metabolism* / Q000652:urine; D008875:Middle Aged; D010375:Pedigree; D011247:Pregnancy; D012463:Saliva / Q000378:metabolism; D013997:Time Factors; D014430:Twins, Monozygotic
chemical_list: D000654:Amobarbital