Formation of cadaverine in the pregnant rat

Polyamines are traps for reactive intermediates in furan metabolism

Furan is toxic and carcinogenic in rodents. Because of the large potential for human exposure, furan is classified as a possible human carcinogen. The detailed mechanism by which furan causes toxicity and cancer is not yet known. Since furan toxicity requires cytochrome P450-catalyzed oxidation of furan, we have characterized the urinary and hepatocyte metabolites of furan to gain insight into the chemical nature of the reactive intermediate. Previous studies in hepatocytes indicated that furan is oxidized to the reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA), which reacts with glutathione (GSH) to form 2-(S-glutathionyl)succinaldehyde (GSH-BDA). This intermediate forms pyrrole cross-links with cellular amines such as lysine and glutamine. In this article, we demonstrate that GSH-BDA also forms cross-links with ornithine, putrescine, and spermidine when furan is incubated with rat hepatocytes. The relative levels of these metabolites are not completely explained by hepatocellular levels of the amines or by their reactivity with GSH-BDA. Mercapturic acid derivatives of the spermidine cross-links were detected in the urine of furan-treated rats, which indicates that this metabolic pathway occurs in vivo. Their detection in furan-treated hepatocytes and in urine from furan-treated rats indicates that polyamines may play an important role in the toxicity of furan.

Determination of rat hepatic polyamines by electron-capture gas chromatography

INTRODUCTION

An efficient and reproducible electron-capture gas chromatographic protocol that allows the simultaneous detection and quantification of the polyamines putrescine (1,4-diaminobutane), cadaverine (1,5-diaminopentane), and spermidine (N-[3-aminopropyl]-1,4-diaminobutane) was developed.

METHODS

Hepatic tissue from male Sprague-Dawley rats was used for analysis. The polyamines and the internal standard (sertraline) were extracted and derivatized with pentafluorobenzoyl chloride (PFBC) under basic aqueous conditions prior to analysis on a gas chromatograph equipped with a capillary column (narrow-bore fused silica column; 25 mm x 0.32 mm) and an electron-capture detector.

RESULTS

PFBC reacts with the amine functions of the polyamines examined here to produce PFB derivatives with high sensitivity on electron-capture detection. The method permitted the quantitative analyses of all three amines in rat hepatic tissue; the concentration of putrescine, but not spermidine, was increased significantly following a 14-day administration of the diamine oxidase (DAO) inhibitor aminoguanidine. Cadaverine was also present at increased concentrations in hepatic homogenates from aminoguanidine-treated rats.

DISCUSSION

Extractive derivatization with PFBC followed by gas chromatographic analysis using electron-capture detection results in a rapid and reproducible assay that permits the simultaneous detection and quantification of putrescine, cadaverine, and spermidine in biological tissue.

Diamine oxidase in relation to diamine and polyamine metabolism

Diamine oxidase catalyzes the oxidative deamination of short chain aliphatic diamines, like putrescine, and histamine. The enzyme is rate-limiting in the terminal catabolism of polyamines, which are endogenous polycations important for cell growth and differentiation. This review examines the behavior of diamine oxidase in mammalian tissues in relation to diamine and polyamine metabolism under physiological and pathological conditions. The role of diamine oxidase in the control of putrescine levels in growing tissues and the known mechanisms responsible for the enzyme expression are also described.

Polyamines and diamine oxidase activity in maternal, embryonal, and fetal tissues of rat after chronic ethanol consumption

The effects of maternal ethanol consumption for 4 weeks before and throughout gestation on polyamine content and diamine oxidase activity of maternal, embryonal and fetal tissues are reported. At the 12th day of pregnancy, a decrease of putrescine in the liver of the mother and marked increases in putrescine, cadaverine and spermidine in embryos were observed. At day 18, putrescine and cadaverine diminished in maternal liver and placenta, and no changes in amine content in fetal liver and brain were found. At day 12, diamine oxidase activity increased in maternal liver and placenta, whereas it greatly diminished in embryos. At day 18, enzyme activity decreased in maternal liver, placenta, fetal liver and brain. These results indicate that chronic ethanol ingestion induces alterations in polyamine concentrations and metabolism in growing and developing tissues during pregnancy that might contribute to the adverse effect of ethanol on conceptual development.

In vitro metabolism of cadaverine in the pregnant rat

The in vitro metabolism of 14C-cadaverine by diamine oxidase was investigated in various tissues of pregnant and non-pregnant rats. The metabolites formed were: delta 1-piperideine, delta-aminovaleric acid, carbon dioxide and some unidentified compound(s). In most of the tissues investigated delta 1-piperideine was the predominant metabolite, but considerable amounts of delta-aminovaleric acid and the unidentified compound(s) were also formed. The oxidative products of cadaverine might be of importance in various physiological and pathophysiological connections associated with elevated diamine oxidase levels.

Changes in cadaverine and putrescine metabolism in the mouse kidney induced to growth by an anabolic steroid

The formation of cadaverine and putrescine was studied in the kidneys of gonadectomized male mice stimulated to growth by nandrolone, an anabolic steroid with low androgenic activity. Administration of nandrolone resulted in an increased kidney weight and elevated activities of lysine and ornithine decarboxylase (assayed by measurement of the formation of 14CO2 from the 1-14C-labelled amino acids). The responses were dose and time dependent. The elevated enzyme activities were reflected by an increased endogenous kidney content of cadaverine and putrescine as well as in an increased urinary excretion of the diamines. Further, the kidney content and the urinary excretion of the polyamines spermidine and spermine were elevated on nandrolone treatment. Fractionation of kidney extracts on pore gradient electrophoresis revealed an apparent molecular weight of about 95 000 Daltons of the lysine decarboxylase as well as of the ornithine decarboxylase. On electrofocusing it was evident that both enzymes were present as more than one isoelectric form. However, the main form in both cases focused at a pH of about 5.0.

Metabolism of putrescine in the pregnant rat

The in vivo metabolism of 14C-putrescine injected to rats before, during and after pregnancy was studied. Within 30 min of the administration of the isotope 9-12% of the injected radioactivity was recorded as 14CO2 in the expired air and after 5 h 60% was expired. The radioactivity excreted in the urine during the first day following the 14C-putrescine administration consisted of unmetabolized putrescine, gamma-aminobutyric acid (GABA) and some unidentified compound(s). No radioactive polyamines were detected in the urine. After treatment of pregnant rats with the diamine oxidase inhibitor aminoguanidine the expiration of 14CO2 was almost completely inhibited. In the urine increased amounts of unmetabolized putrescine were excreted while the excretion of GABA and the unidentified compound(s) were decreased. In addition 14C-spermidine appeared in the urine. The in vitro metabolism of putrescine was determined by the incubation of different tissues of pregnant and non-pregnant rats with 14C-putrescine. The 14C-metabolites derived via the diamine oxidase pathway (delta 1-pyrroline, GABA, some unidentified compound(s) and carbon dioxide) varied in magnitude with the tissue investigated. GABA was found to be a main metabolite of putrescine in several tissues of the pregnant rat. The content of putrescine and spermidine was elevated in several tissues as well as the blood on the 19th day of pregnancy in rats treated with aminoguanidine, while the content of spermine was unchanged.