Untersuchungen zur Hydroxylierung von Acetanilid mit Lebermikrosomen normaler und skorbutischer Meerschweinchen

Abstract

It is possible to differentiate between normal and manifestly scorbutic guinea pigs and apparently healthy animals, which are latently scorbutic, by the determination of the ascorbic acid content of the adrenals, the liver nuclei and the liver mitochondria. The enzymatic p-hydroxylation of acetanilide by guinea pig liver microsomes with NADPH [reduced nicotinamide adenine dinucleotide phosphate] as the electron donor decreases as soon as the dietary supply of ascorbic acid is decreased, i.e., in the latently scorbutic animal, in the manifestly scorbutic animal, the activity is about 10% that of the original. Administration of dehydro-ascorbic acid in vivo, 1 hr. before killing, causes an increase in the ascorbic acid content of the liver as well as in the enzymic p-hydroxylation by the liver microsomes. Ascorbic acid (the actual agent is semidehydroascorbic acid) is apparently a single electron donor in vivo in the microsomal hydroxylation. Ascorbic acid is indeed the physiological activator for this reaction, but it is not specific, e. g., it can be replaced in vitro by dihydroxyfumarate.