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Biomedical subjects

G Rentsch

Publications and source records attributed to G Rentsch.

At least 19 recordsLinked to original sources

The relevance of drug-induced organ pigmentation in animals.

Postmortem examination of animals from long-term safety evaluation studies often reveals pigment deposition in tissues. A review of several such observations is given and the possible chemical backgrounds of their origin are described, in an attempt to aid the determination of relevance in individual cases. It is suggested that one may be fairly broad-minded in the interpretation of the relevance of such pigments, especially if they are found only in one species, and have no influence on the function of the organs involved. A final answer comes only after administration of the particular drug to man, although he is normally dosed at all events one should not overvalue the relevance of pigmentation found in long-term animal studies.

Animals↗

The effect of prolonged administration of allylisopropylacetylurea to rats on cytochrome P-450 and other liver haemoproteins.

1. The effect of long-term administration, including recovery, of allylisopropylacetylurea to rats was investigated. 2. In the liver, cytochromes P-450, b5, catalase and 5-aminolaevulinic acid synthetase were measured. Serum glutamate-pyruvate, transaminase, glutamate-oxalacetate transaminase and alkaline phophatase were determined to assess cell damage, while urinary coproporphyrin and uroporphyrin were measured to assess the degree of porphyia. 3. In the liver the lowering of cytochrome P-450 and catalase was paralleled by an increase in 5-aminolaevulinate synthetase. Cytochrome b5 was only marginally affected. 4. Rats recover well from long-term treatment with high doses of allylisopropylacetylurea and revert to normal values for parameters measured. 5. A mechanism for the intracellular action of allylisopropylacetylurea on cytochrome P-450 and other haem-containing compounds is presented.

5-Aminolevulinate Synthetase↗

[Relevance of enzyme histochemistry of rat thyroid gland].

High doses of aniline analgesics produced increased lipofuscin accumulation in rats thyroid glands after 18 week's treatment. To assess the significance of this change histochemical, biochemical and functional tests have been performed. Increased benzidineperoxidase, decreased acid phosphatase and unchanged leucyl-beta-naphtylamidase activities have been found histochemically and partly confirmed by biochemical methods. 131I-uptake was unchanged and PBI-levels decreased. The selection of appropriate histochemical methods in combination with additional techniques is stressed.

Acetaminophen↗