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PubMed1983

An autoradiographic study of delta-aminolevulinic acid uptake by mouse brain.

delta-Aminolevulinic acid (ALA), a toxic precursor of porphyrin, when injected i.v. failed to enter most brain structures, such as the cortex, thalamus, midbrain, and others, as determined by the autoradiographic technique. However, the choroid plexus, median eminence, and a narrow strip of the periventricular zone, which usually lack a barrier function, were labeled in these experiments. These results indicate that the blood-brain barrier is virtually impermeable for ALA, although the amino acid may enter the cerebrospinal fluid via fenestrated capillaries of the circumventricular organs and tanycytes of the median eminence.

Aminolevulinic Acid↗
PubMed1986

Genetic differences in the effects of delta-aminolevulinic acid on seizure latency in mice.

delta-Aminolevulinic acid, an intermediate in heme formation, is elevated in certain human disorders including acute intermittent porphyria, tyrosinemia, and lead poisoning. It has been implicated in the central nervous system manifestations of these disorders via interactions with the GABAergic system. This potential interaction was examined by testing whether or not delta-aminolevulinic acid could alter the latency to seizure in mice. Seizures were induced in a variety of inbred strains of mice including C57BL, C3H, DBA mice and in a heterogeneous stock of mice. Flurothyl and 3-mercaptopropionic acid were used to induce seizures in the presence and absence of delta-aminolevulinic acid administered either i.p. (0.5 and 1.5 mmol/kg), or i.c.v. (4.5 and 450 nmol). delta-Aminolevulinic acid increased the latency to myoclonic and clonic seizures induced by flurothyl when administered i.p.; i.c.v. injections also delayed clonic seizures induced by flurothyl, and increased the latency to tonic seizures induced by 3-mercaptopropionic acid. The degree to which delta-aminolevulinic acid altered seizure latency in all tests was dependent on strain of mouse tested. These data support the conclusion that delta-aminolevulinic acid can act as an anticonvulsant agent, and mimic the effects of GABA. Moreover, there is genetic variation in the sensitivity of the various strains of mice to delta-aminolevulinic acid.

Aminolevulinic Acid↗
PubMed1987

Urinary excretion of 5-hydroxyindoleacetic acid, delta-aminolevulinic acid and coproporphyrin isomers in rats and men exposed to lead.

The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), delta-aminolevulinic acid (ALA) and coproporphyrin (CP) isomers (I and III) was investigated in rats and workers exposed to lead. Urinary excretion of 5-HIAA, which is the major metabolite of serotonin, was not influenced by the lead exposure. However, a significant increase in urinary ALA and CP was found in rats and workers exposed to lead. In particular, the urinary excretion of CP-III was markedly increased compared to that of CP-I in rats and workers exposed to lead.

Administration, Oral↗
PubMed1988

Species difference of urinary excretion of delta-aminolevulinic acid and coproporphyrin in mice and rats exposed to lead.

The urinary excretion of delta-aminolevulinic acid (ALA) was first investigated in mice exposed to lead in the drinking water (500 ppm) for 30 days, and the results were compared with those obtained from rats exposed to lead under the same exposure condition. The result indicated that the level of urinary ALA excretion in lead-exposed mice was much higher than that in lead-exposed rats. This finding suggests a species difference between mice and rats with regard to sensitivity to lead. On the other hand, urinary coproporphyrin (CP) was also determined in rats and mice exposed to lead. The result obtained indicated that the increasing level of urinary CP excretion was higher in rats than in mice, contrary to expectation. The reason for the discrepancy between urinary excretion of ALA and that of CP in rats and mice exposed to lead is, however, unknown.

Aminolevulinic Acid↗
PubMedDate not supplied

Renal reabsorption and secretion of delta-aminolevulinic acid in the rat.

Renal mechanisms for handling delta-aminolevulinic acid (ALA) were investigated in control and lead-exposed rats infused with ALA at a range of rates which produced plasma ALA as high as 2380 ng/mL. The presence of both reabsorption and secretion mechanisms was demonstrated. Reabsorption is the more efficient of the two mechanisms at low plasma ALA concentrations, and masks secretion in this range. Net secretion is observed at very high plasma ALA concentrations. Exposure to up to 2000 micrograms lead/mL of drinking water for 12 to 18 months had no measurable effect on net ALA excretion at a given plasma ALA level.

Absorption↗
PubMed1970

Activation of delta-aminolaevulate synthetase in extracts of Rhodopseudomonas spheroides.

1. The spontaneous activation of delta-aminolaevulate synthetase in extracts from Rhodopseudomonas spheroides grown semi-anaerobically in the light requires oxygen and does not take place anaerobically in the dark. 2. Activation is completely prevented by azide or cyanide and is partially inhibited by chlorpromazine. These compounds inhibit markedly the succinoxidase activity of extracts. 3. NADH delays activation, but when it has been oxidized by the extract activation begins at the normal rate and complete activation occurs. By contrast both the rate and the extent of activation are markedly decreased by even small amounts of carboxylic acids. 4. The inhibitory effects of succinate and citrate on activation can be prevented by malonate and fluorocitrate respectively. 5. These results suggest that for activation to occur some endogenous compound has to be oxidized via the electron transport chain. 6. Activation occurs under anaerobic conditions in the light, probably by photo-oxidation.

Amino Acids↗
PubMed1984

Regulation of delta-aminolaevulinic acid synthesis and protochlorophyllide regeneration in the leaves of dark-grown barley (Hordeum vulgare) seedlings.

Laevulinic acid (Lev) was used to control the rate of protocholorophyllide (PChl) regeneration in the leaves of dark-grown seedlings of barley (Hordeum vulgare) after a brief light treatment. In the leaves given Lev, at concentrations that severely block the resynthesis of protochlorophyllide, there was a massive overproduction of delta-aminolaevulinic acid (AmLev) that was well in excess of that required for the regeneration of PChl observed in the control leaves. Lev, at low concentrations, slightly delayed regeneration and held up, rather than inhibited, the utilization of the AmLev, which accumulated in the tissues. The overproduction and uncontrolled formation of AmLev also occurred in dark-grown leaves treated with a high concentration of Lev and given a light treatment of just sufficient energy to photoreduce only small quantities of the endogenous PChl. Experiments in which a high level of free PChl was induced by incubating the leaves in AmLev indicated that the active species of PChl was that associated with, and bound to, the PChl reductase protein. The results strongly demonstrate a close relationship between the PChl-protein complex and the ability of the leaves to synthesize AmLev.

Aminolevulinic Acid↗
PubMed1969

Soluble hepatic delta-aminolevulinic acid synthetase: end-product inhibition of the partially purified enzyme.

The present study confirms the existence of hepatic delta-aminolevulinic acid synthetase in the cytosol of the liver, suggests that this enzyme may be in transit to the mitochondria, and defines some of the characteristics of the partially purified enzyme. The substrate and cofactor requirements are similar to those of mitochondrial delta-aminolevulinic acid synthetase. Heme strongly inhibits the partially purified enzyme. A number of proteins that bind heme block this inhibition, which explains previous failures to demonstrate heme inhibition in crude systems. End-product inhibition of delta-aminolevulinic acid synthetase in the mitochondria may play an important role in the regulation of heme biosynthesis in eukaryotic cells.

Acyltransferases↗
PubMedDate not supplied

Urinary delta-aminolevulinic acid as a biological indicator throughout penicillamine therapy in lead intoxication.

A group of 121 patients with occupational lead exposure was studied. Saturnism was confirmed in 42 of them. Patients were given D-penicillamine in doses of 0.75 and 1.5 g/day. Urinary delta-aminolevulinic acid was selected as a toxicity biological indicator; its concentrations were quantified daily during therapy. Urinary delta-aminolevulinic acid is considered a good biological indicator throughout penicillamine therapy and also in the detection of lead intoxication. Likewise, the chelating test is considered an excellent method to confirm the diagnosis of lead poisoning.

Aminolevulinic Acid↗
PubMed1981

Accumulation of protoporphyrin IX from delta-aminolevulinic acid in bovine skin fibroblasts with hereditary erythropoietic protoporphyria. A gene-dosage effect.

Bovine skin fibroblasts accumulated protoporphyrin IX when incubated in culture with the porphyrin-heme precursor, delta-aminolevulinic acid (ALA). Fibroblasts from cattle homozygous for erythropoietic protoporphyria (EPP) and with the clinical symptoms of the disease accumulated approximately sixfold greater amounts of protoporphyrin IX than cells from normal control animals. Cells from obligatory heterozygous animals, which are clinically normal, accumulated an intermediate level of protoporphyrin IX. When these cells were incubated with ALA and CaMg EDTA, all types of cells accumulated approximately the same amount of protoporphyrin IX (approximately 500 nmol/mg protein), suggesting that ferrochelatase activity was equally low after inhibition by treatment with CaMg EDTA in all cells. Thus the ratio of protoporphyrin IX accumulation from ALA in cultures treated with CaMg EDTA compared with controls treated with ALA alone was greatest in normal cells, least in EPP cells, and intermediate in the heterozygote cells. These findings suggest that the amount of protoporphyrin IX accumulation from ALA reflects the extent of deficiency of ferrochelatase and is proportional to the dosage of abnormal EPP gene in cultured fibroblasts. Similarly, stimulation of porphyrin accumulation by CaMg EDTA reflects diminished ferrochelatase activity in these cells. Thus, the results of this study demonstrate the usefulness of estimating protoporphyrin IX formation from ALA for the detection of an EPP gene defect in cultured bovine skin fibroblasts.

Aminolevulinic Acid↗
PubMed1975

Biosynthesis of liver catalase in rats treated with allylisopropylacetylcarbamide. II. Double-labeling of catalase with (14C)leucine and delta-(3H)aminolevulinic acid.

Double-labeling of liver catalase [EC 1.11.1.6] with [14-c]leucine and delta-[3H]aminolevulinic acid was carried out both in vivo and in vitro using rats treated with allylisopropylacetylcarbamide (Sedormid). These radioactive precursors were incorporated into catalase at a lower rate than in normal rats. In particular, the incorporation of 3H was remarkably inhibited. The results suggest that the administration of Sedormid can inhibit synthesis of the protein moiety of catalase, and possibly interfere with the binding of heme to the catalase protein.

Aminolevulinic Acid↗
PubMed1989

5-Aminolevulinic acid synthesis in Escherichia coli.

A hemA mutant of Escherichia coli containing a multicopy plasmid which complemented the mutation excreted 5-aminolevulinic acid (ALA) into the medium. [1-14C]glutamate was substantially incorporated into ALA by this strain, whereas [2-14C]glycine was not. Periodate degradation of labeled ALA showed that C-5 of ALA was derived from C-1 of glutamate. The synthesis of ALA by two sonicate fractions which had been processed by gel filtration and dialysis, respectively, was dependent on glutamate, ATP, NADPH, tRNA(Glu), and pyridoxal phosphate. tRNA(Glu) stimulated ALA synthesis in a concentration-dependent manner. Pretreatment with RNase reduced this stimulation. The amino acid sequence of the cloned insert, derived from the nucleotide sequence (J.-M. Li, C. S. Russell, and S. D. Cosloy, J. Cell Biol. 107:617a, 1988), showed no homology with any ALA synthase sequenced to date. These results suggest that E. coli synthesizes ALA by the C5 pathway from the intact five-carbon chain of glutamate.

Adenosine Triphosphate↗