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Biomedical subjects

W W Weber

Publications and source records attributed to W W Weber.

At least 91 records · Page 5Linked to original sources

Failure of commercially prepared isoniazid diet to produce isoniazid serum concentrations in rhesus monkeys.

A comparison was made of serum isoniazid concentrations and the time course of isoniazid elimination in rhesus monkeys given the drug im, orally on sugar cubes, or in a commercially medicated diet. When the drug was administered orally on sugar cubes or im, peak serum concentrations were usually reached within 2 hr. A threefold individual variation in the rate of elimination was noted, and in most animals the serum concentration at 6 hr approached zero. Isoniazid was not detected in the serum of any animal receiving the commercially medicated diet. Others using this medicated food in their tuberculosis prophylaxis programs should be aware that the diet probably does not provide therapeutically effective dosage to the animals.

Administration, Oral↗

Multiple N-acetyltransferases and drug metabolism. Tissue distribution, characterization and significance of mammalian N-acetyltransferase.

Investigations in the rabbit have indicated the existence of more than one N-acetyltransferase (EC 2.3.1.5). At least two enzymes, possibly isoenzymes, were partially characterized. The enzymes differed in their tissue distribution, substrate specificity, stability and pH characteristics. One of the enzymes was primarily associated with liver and gut and catalysed the acetylation of a wide range of drugs and foreign compounds, e.g. isoniazid, p-aminobenzoic acid, sulphamethazine and sulphadiazine. The activity of this enzyme corresponded to the well-characterized polymorphic trait of isoniazid acetylation, and determined whether individuals were classified as either ;rapid' or ;slow' acetylators. Another enzyme activity found in extrahepatic tissues readily catalysed the acetylation of p-aminobenzoic acid but was much less active towards isoniazid and sulphamethazine. The activity of this enzyme remained relatively constant from individual to individual. Studies in vitro and in vivo with both ;rapid' and ;slow' acetylator rabbits revealed that, for certain substrates, extrahepatic N-acetyltransferase contributes significantly to the total acetylating capacity of the individual. The possible significance and applicability of these findings to drug metabolism and acetylation polymorphism in man is discussed.

Acetyltransferases↗

Pharmacogenetics.

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Analgesics↗

Protein binding.

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Chemical Phenomena↗