In a previous paper, we showed inhibition of rat liver L-threonine dehydrogenase by a preparation obtained by dialysis and concentration from rat liver mitochondria stored at -20 degrees C for 7-10 days (Pagani, R., Leoncini, R., Guerranti, R. and Marinello, E. (1990) It. J. Biochem. 39, 106-114). The chemical composition of the fraction containing the unknown 'inhibitor' has now been studied and identified as D-3-hydroxybutyrate (D3HB).

3-Hydroxybutyric Acid↗

PubMed1995

Separation and determination of liver uric acid and allantoin.

We previously described the only satisfactory procedure yet achieved for separating uric acid and allantoin from rat liver. The procedure was based on trichloroacetic acid (TCA) extraction, acid hydrolysis, treatment with Hg-acetate, and cation- and anion-exchange chromatography. After separation, allantoin was quantified by a colorimetric method, and uric acid enzymatically using uricase. Since this procedure is too time-consuming, we propose an improved version which avoids the need for anion-exchange chromatography and the complex assay of catabolic compounds. The new method consists of a very fast and simple HPLC separation and direct determination of uric acid and allantoin at 220 nm. The method can be used for fresh tissue or after treatment of the tissue with labeled precursor.

Allantoin↗

PubMed1995

The influence of testosterone on purine nucleotide metabolism in rat liver.

Purine nucleotide metabolism was studied in rat liver by following the incorporation of 14C-formate into soluble nucleotides, uric acid and RNA ribonucleotides. After castration, GMP formation was less than that of AMP, and purine nucleotide catabolism and RNA synthesis decreased. Testosterone administration did not modify GMP or AMP synthesis, but restored purine nucleotide catabolism and RNA production to normal values. These results demonstrate the influence of testosterone on purine nucleotide metabolism in a non-reproductive organ.

Animals↗

PubMed1995

Purine nucleotide metabolism in lymphocytes of B-cell chronic lymphocytic leukemia patients.

Purine nucleotides were studied in human peripheral blood lymphocytes from normal subjects and patients with chronic B-cell lymphocytic leukemia (B-CLL). Nucleotide content was determined by high performance liquid chromatography (HPLC). The overall rate of purine nucleotide synthesis was measured following the incorporation of 14C-formate into the nucleotides of a lymphocytic suspension. Results indicate a substantially reduced rate of purine nucleotide metabolism.

Aged↗

PubMed1995

[The nucleotide pool in subjects with rheumatoid arthritis and its seasonality].

Explore the source record for details and available documents.

Adult↗

PubMed1995

Morphometric evaluation of rat liver after castration: effects of testosterone.

In men and animals subject to orchiectomy, varying degrees of hypotrophy have often been observed, even involving non-reproductive organs. Liver hypotrophy appears particularly interesting in view of the metabolic alterations that could possibly ensue. We have applied the morphometric approach to the study of this kind of hypotrophy in castrated rats and in animals receiving a substitutive, testosterone-based treatment after castration. The morphometric model adopted was built on the basis of an interactive approach, using an image analyser (IBAS) with specially-designed software, and consists of number and size, as well as surface and volume fractions, of hepatocytes, their nuclei, cytoplasm, and the relevant relation to the sinusoidal bed. The effects of castration were revealed by a reduction of the mean volume of hepatocytes, associated with a reduction of the sinusoidal bed. Such reduction is correspondingly associated with an increase of the extraparenchymal components (endothelia, Glisson capsule). In the testosterone-treated group, while no appreciable symptoms of retrieval were yet observable in the volume of hepatocytes, the sinusoidal bed was instead superimposable onto the control group data as far as both volume and blood/hepatocyte interface were concerned. In the castrated animals the number of hepatocytes per mm3 was found to be increased. The group of testosterone-administered rats also showed a high level for this parameter which, associated with the spread of the capillary bed, could be compatible with a picture of precocious hyperplastic response to the therapy. The correlation between the available morphometric data and the biochemical results which are being currently sought will further clarify the meaning of this phenomenon.

Animals↗

PubMed1994

The regulation of alanine and aspartate aminotransferase by different aminothiols and by vitamin B-6 derivatives.

We examined the effects on alanine aminotransferase and aspartate aminotransferase of different aminothiols (L-cysteine, D-cysteine, cysteamine, L-cysteine ethyl ester, L-cysteine methyl ester) and several vitamin B-6 derivatives (pyridoxal, pyridoxamine, pyridoxol, pyridoxol 5'-phosphate), before and after treatment with KOCN, which transforms these molecules into the corresponding carbamoyl derivatives. Only GPT, and not GOT, was specifically inhibited by L-cysteine and, to a lesser extent, by D-cysteine. The association reaction: PLP + apo GPT<-->holo GPT was inhibited by the vitamin B-6 derivatives, and this inhibition was prevented by pretreatment of the vitamin B-6 derivatives with KOCN. All the observed effects occurred at pH 7, 37 degrees C, at mM and even lower concentrations of reagents. Hence, they all potentially play a physiological role, in the regulation of the PLP dependent enzymes and of the vitamin B-6 levels in the cell.

Alanine Transaminase↗

PubMed1994