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PubMed1979

Steroid induction of delta-aminolevulinic acid synthase and porphyrins in liver. Structure-activity studies and the permissive effects of hormones on the induction process.

Quantitative aspects and structure-activity relationships of the inducing effects of natural steroids on delta-aminolevulinic acid (ALA) synthase and porphyrins have been investigated in monolayer cultures of chick embryo liver cells maintained in a serum-free medium as well as in the chick embryo liver in ovo. Many 5 alpha and 5 beta metabolites of neutral C-19 and C-21 hormones and hormone precursors stimulated porphyrin formation and ALA-synthase induction in the cultured liver cells as we have previously described. In these inducing actions a number of 5 beta epimers (A:B cis) were found to be more potent than their corresponding 5 alpha epimers (A:B trans). The structure-activity relationship between 5 beta and 5 alpha steroid epimers with respect to ALA-synthase induction in culture was also found to prevail with respect to induction of this enzyme in chick embryo liver in ovo. Hemin in concentrations of 2 x 10(-7) M inhibited steroid induction of porphyrin formation, and CaMgEDTA enhanced the responsiveness of the cultured liver cells to steroids by approximately 10 times. The addition of insulin, or insulin plus hydrocortisone or insulin plus hydrocortisone plus triiodothyronine, was important for the maintenance of protein synthesis and essential for maximal expression of the ability of steroids to induce porphyrins and ALA-synthase in the "permissive" effect which insulin, hydrocortisone, and triiodothyronine exert on allylisopropylacetamide induction of porphyrins and ALA-synthase also extends to the induction process which is elicited by natural steroids. These findings also strongly suggest that the regulation of hepatic porphyrin-heme biosynthesis by endogenous as well as exogenous chemicals is significantly influenced by the internal hormonal milieu.

5-Aminolevulinate Synthetase↗
PubMed2003

Changes of urinary and blood porphyrin profiles by exposure to PCBs, lead or diazinon in rats.

Porphyrin profiles in excreta or blood have been useful biomarkers for monitoring exposure of hazardous xenobiotics to human or animals. We evaluated and compared the changes in urinary and blood copro-, uro-, and protoporphyrins during and after the exposure of Aroclor1254 (PCBs), lead (Pb) or diazinon to rats. PCBs (10, 50 and 100 mg/kg bw), Pb (62.5, 250 and 1,000 ppm) and diazinon (10, 30 and 90 mg/k bw) were administered to rats via gavage (PCBs and diazinon) or via drinking water (Pb) daily for 5 w. Urine and blood were collected weekly for the 5 w of exposure and for 5 w after withdrawal. Three urinary porphyrins and blood protoporphyrin increased gradually with PCB dose in a time dependent manner and remained elevated for 5 w after withdrawal. Urinary porphyrins were increased rapidly by Pb and then returned to normal immediately after Pb withdrawal while blood protoporphyrin remained high but gradualy decreased during the 5 w after withdrawal. Diazinon did not affect blood and urinary porphyrins as did PCBs and Pb, but just induced a weak increase of urinary coproporphyrin. Urinary and blood porphyrin profiles can be used as biomarkers for exposure assessment to PCBs and Pb. The normal ranges of blood porphyrins in cattle, pigs, chickens and rats were also established for use as biomarkers.

Administration, Oral↗
PubMed2001

[Synthesis and ultraviolet-visible spectrum of two new symmetrical porphyrins].

Meso-tetra(p-benzoylaminophenyl) porphyrin or meso-tetra (o-benzoylaminophenyl) porphyrin are synthesized by condensation of meso-tetra (p-aminophenyl) porphyrin or meso-tetra (o-aminophenyl) porphyrin and benzoyl chloride in DMF using NaOH as catalyst, these porphyrins and the method have not been reported previously. Their structures are ascertained by elemental analysis, ultraviolet-visible spectrum, IR and 1H-NMR measurements. The ultraviolet-visible spectrum of the two porphyrins is discussed in detail.

Molecular Structure↗
PubMed2003

Long-standing changes in the urinary profile of porphyrin isomers after clinical remission of porphyria cutanea tarda.

Patients with overt porphyria cutanea tarda (PCT) show a distinctive and abnormal urinary profile of porphyrin excretion. It is not known, however, whether clinical remission of the disease produces complete normalization of this profile. We selected 46 patients, previously diagnosed with PCT, who after treatment presented normal levels of total porphyrins in urine (< 35 nmol/mmol creatinine). We analyzed their urine specimens by hplc to identify and quantify the various porphyrins and we compared the urinary porphyrin profiles to those of 40 healthy volunteers. While healthy volunteers gave a pattern dominated by excretion of coproporphyrin III, 80% of the PCT patients in clinical remission showed the characteristic profile of PCT, with decreased coproporphyrin-to-uroporphyrin ratio and/or inversion of the normal coproporphyrin III-to-coproporphyrin I ratio. Detection of uroporphyrin III and heptacarboxyl III intermediates was significantly more common among the patients than the controls (p < 0.05). This study shows that PCT patients demonstrate persistent changes in urinary porphyrin profiles during clinical remission, even when total urinary porphyrin excretion has fallen to the normal range.

Adult↗
PubMed1992

Clearance times of porphyrin derivatives from mice as measured by in vivo fluorescence spectroscopy.

The clearance times of 17 different porphyrin derivatives from SKH:HR-1 mice have been measured using the technique of in vivo fluorescence spectroscopy. This technique monitors the in vivo porphyrin fluorescence observed from the external skin surface. Most hydrophilic porphyrin derivatives show relatively short clearance times, in the order of 2.5-6 h. The dicarboxylic acid porphyrins, proto-, hydroxyethylvinyldeutero- and hematoporphyrin IX have clearance times of 7.8, 12.2 and 14.7 h respectively. The mixture hematoporphyrin derivative has an intermediate clearance time of 12.6 h. N-methylated porphyrins show clearance times in the vicinity of 15-22 h. Monoaspartyl chlorin e6 shows the longest clearance time of all porphyrin derivatives measured (30.3 h).

Animals↗
PubMed2006

[The combination of carbohydrate and porphyrinic exchange disturbances: is it a chance or regularity?].

The subjects of the study were 399 patients with internal diseases and metabolic disturbances. Carbohydrate exchange parameters (fasting level of capillary blood glucose and glucose tolerance test), and porphyrin fractions in urine (uroporphyrin, coproporphyrin), and feces (protoporphyrin, coproporphyrin) were measured. Hepatic type of porphyrinic dysmetabolism was registered in 201 (50.4%) patients. Out of these patients, 38 had disturbances corresponding to the criteria of symptomatic elevation of fecal porphyrin level, 28 had secondary coproporphyrinuria, 40 had latent, and 95 had manifest late cutaneous porphyria. In patients with normal porphyrinic exchange, the frequency of carbohydrate exchange disturbances did not exceed 6%, while in patients with different variants of porphyrinic dysmetabolism it was almost 40%. The results show that patients with hepatic type of porphyrinic dysmetabolism should be considered to have a higher risk of the development of diabetes mellitus and other carbohydrate disorders.

Adolescent↗
PubMed1985

Ability of several hexachlorobenzene metabolites to induce porphyrin accumulation in chick embryo liver "in ovo".

The present study investigates the ability of several hexachlorobenzene (HCB) metabolites to induce porphyrin accumulation in chick embryo liver cells in ovo, in order to further clarify the role of metabolites in the mechanism of HCB-induced porphyria. HCB per se had no effect on liver porphyrin content, but pretreatment assays with phenobarbital suggested that its metabolic products did. When the direct effect of phenolic, sulfur-containing, and benzenic metabolites of HCB were tested, the following results were obtained. Less chlorinated benzenes (pentachlorobenzene and 1,2,3,4- 1,2,3,5- 1,2,4,5- tetrachlorobenzene) had poor capacity to change the control porphyrin content. On the other hand, the behavior of phenolic metabolites (pentachlorophenol, 2,3,4,5- 2,3,4,6- 2,3,5,6- tetrachlorophenol, 2,3,4- 2,3,5- 2,3,6- 2,4,5- 2,4,6- 3,4,5- trichlorophenol and tetrachlorohydroquinone) as porphyrin inducers was remarkable; the stronger effects were produced by trichlorophenols and tetrachlorohydroquinone. Sulfur containing metabolites produced increases in porphyrin content that were lower than those produced by phenolic compounds and higher than those due to the action of less chlorinated benzenes; only 1-methyl-(2,3,4,5-pentachlorophenyl) sulfoxide was not able to increase porphyrin level. The extent of the effect of the other drugs was pentachlorothiophenol greater than 1-methyl-(2,3,4,5,6-pentachlorophenyl) sulfone greater than tetrachlorothioanisol greater than pentachlorothioanisol. Regarding the mechanism of HCB porphyria, the present results indicate that phenolic metabolites and, in a lower degree, sulfur-containing metabolites, can contribute to the porphyrinogenic ability of HCB.

Animals↗
PubMed1987

Patterns of porphyrin excretion in feces as determined by liquid chromatography; reference values and the effect of flora suppression.

While determining reference values for porphyrins in feces as measured by liquid chromatography, we observed strong fluctuations in fecal porphyrin contents. To explain these fluctuations, we selectively suppressed the intestinal flora of healthy persons. Suppression of aerobic flora had no effect on fecal porphyrin excretions, whereas suppression of anaerobic flora completely inhibited the transformation of protoporphyrin to pempto- and deuteroporphyrin for as long as five days after stopping medication. During this latter, the conversion to mesoporphyrin was clearly increased in one person and in others partly affected or decreased. During complete suppression of flora for prolonged periods, the production of proto- and coproporphyrins was decreased and deutero-, pempto-, and mesoporphyrins were absent. We conclude that the nature of fecal porphyrins is mostly affected by action of anaerobic bacteria, different kinds of bacteria having different effects. Some, like aerobic Gram-negative bacteria, have little or no effect on porphyrins; some cause production of mesoporphyrin; some promote a conversion to pempto- and deuteroporphyrin; and some mainly cause production of copro- and protoporphyrin. We give examples in which normal to slightly increased excretions of fecal porphyrin do not exclude a diagnosis of porphyria, and relatively high concentrations do not confirm one.

Bacteria↗
PubMed1985

Sorbent therapy of the porphyrias. IV. Adsorption of porphyrins by sorbents in vitro.

The adsorption capacities (Qm's) of the ion exchange resin cholestyramine and 8 activated charcoals for uroporphyrin, protoporphyrin and coproporphyrin, porphyrins that accumulate within tissues or vasculature in certain porphyrias, have been determined. Qm's (mg porphyrin/gm dry sorbent) were derived from Langmuir isotherms, which were constructed from experiments that assessed the amount of porphyrin adsorbed after the addition of varying amounts of porphyrin in solution to a constant amount of sorbent. These experiments were carried out at pH 8.2 in 0.5% desoxycholate, to simulate conditions of the small intestine. For uroporphyrin I, the Qm for Amoco Supersorb PX-21 highly activated charcoal was greater than that for cholestyramine (mean +/- SD of 26.5 +/- 12.7 vs. 17.0 +/- 2.6; t'32 = 2.46, P less than 0.025) and highly significantly greater than those of the other charcoals. For protoporphyrin IX, cholestyramine and Amoco Supersorb PX-21 charcoal had the highest Qm's (32.4 +/- 8.6 and 30.9 +/- 9.2), but these were not significantly greater than the Qm's of 5 other charcoals. Little difference was found among sorbents in the rate of adsorption of either porphyrin. For coproporphyrin III, the Qm's of cholestyramine and Amoco Supersorb PX-21 charcoal were not significantly different (39.2 +/- 13.7 vs. 35.1 +/- 4.0) but they were greater than that of Norit USP XX (20.0). Virtually no desorption of porphyrin from either cholestyramine or Amoco Supersorb PX-21 charcoal was detected. Both cholestyramine and Amoco Supersorb PX-21 charcoal appear to be highly avid sorbents for porphyrins of varied states of carboxylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1979

The effect of tumor localizing porphyrins on the conversion of fibrinogen to fibrin.

The interaction of hematoporphyrin IX and two synthetic porphyrin tumor localizers, meso-tetra (4-carboxyphenyl) porphine (TCPP) and mesotetra (4-sulfonatophenyl) porphine (TPPS4) with fibrinogen was investigated in the presence and absence of light. Both TPPS4 and TCPP were found to bind to fibrinogen in greater than a 1/1 mole ratio in the absence of light. Chromatographic analysis indicated that during illumination TPP4 bound to fibrinogen to a greater extent that did either TCPP or hematoporphyrin. Both TCPP and TPPS4 were found to exhibit a greater inhibitory effect on clotting in the presence of light than did hematoporphyrin. In the absence of light and added Ca2+, both TCPP and TPPS4 were found to stimulate clotting at very specific porphyrin/fibrinogen concentration ratios, with TPPS4 being the more potent stimulator of the two. Hematoporphyrin exhibited little or no effect on clotting times. Fibrinogen, photoirradiated in the presence of the porphyrins was found to inhibit the clotting of unirradiated fibrinogen. A comparison of the stimulatory effects on clotting times by either calcium or TCPP and TPPS4 indicated that the porphyrins were capable of eliciting a greater stimulatory response than did calcium. The magnitude of the stimulatory response caused by the porphyrins alone was substantially reduced in the presence of calcium although the overall stimulatory response was increased but not additive. This suggests some interaction between either the calcium and porphyrin molecules or similarities in the respective stimulatory mechanism(s) involved. A possible correlation between these observations and the porphyrins ability to localize in tumors is also discussed.

Blood Coagulation↗
PubMed1982

The particular traits of carcinogenesis induced in Wistar rats by aflatoxin B1. IV. Porphyrins and the activity of gamma-glutamyltranspeptidase in Wistar rats bearing transplantable hepatoma.

In inbred Wistar rats bearing transplantable hepatoma induced by aflatoxin B1 tissue porphyrins and the level of the serum gamma-glutamyltranspeptidase (GGTP) were studied. A liver reaction in carriers of transplants was ascertained, that was expressed especially by an increase in porphyrins, mainly the protoporphyrin fraction, and by morphological changes. The content of porphyrins in lung metastases was higher than in hepatomas and livers. The level of serum GGTP was higher in females up to the 40th passage, and up to the 90th passage higher in males. Hormonal conditioning of the early AFB1-hepatoma passages is supported by a lower level of serum GGTP in females and higher in males, and the liver and tumor porphyrins in animals previously castrated in comparison with uncastrated rats. Comparative data of the quantity and quality of porphyrins in different rat tissues with primary and transplantable AFB1-hepatomas demonstrate that systemic metabolic disorders of porphyrins are greater in rats with primary than in the case of transplantable tumors.

Aflatoxin B1↗
PubMed1984

Spectral studies of horse heart porphyrin cytochrome c.

Removal of the heme iron from cytochrome c to generate porphyrin cytochrome c relieves the quenching of porphyrin fluorescence and enhances the fluorescence of the single tryptophan residue and the 4 tyrosine residues. The intensity of the porphyrin fluorescence is not perturbed by denaturation of the protein at neutral pH using either urea or guanidine hydrochloride. However, the amplitude of tryptophan fluorescence is increased by these denaturants from 5 to about 85% of a model tryptophan residue using solutions of 2 microM tryptophan. In contrast to cytochrome c, the tryptophan fluorescence amplitude of denatured porphyrin cytochrome c is independent of pH over the range pH 3.0 to 7.4. Acidification of solutions of either native or denatured porphyrin cytochrome c markedly alters both the visible absorbance and fluorescence of the protein consistent with protonation of two pyrrole nitrogens on the porphyrin. Preliminary analysis of the spectral changes occurring in the acid transition suggests the presence of an intermediate form having only one of these two pyrrole nitrogens protonated.

Animals↗
PubMedDate not supplied

[Diabetes mellitus and the biosynthesis of porphyrins].

The blood and urine porphyrin content and porphyrin biosynthesis in the red blood cells after delta-amino levulinic acid (ALA) incubation, porphobilinogen and non-consumed ALA levels, porphobilinogen-synthetase activity were studied in 86 patients divided into 3 groups depending on diabetes severity. Porphyrin separation was investigated by means of thin-layer chromatography. It was found that porphyrin biosynthesis decreases in all diabetics at the early periods of the disease, not depending on its severity. Porphyrin biosynthesis is lowered during a phase of chronic renal insufficiency in patients with diabetic nephropathy. Porphyrin metabolic disorder is caused by hepatic dysfunction and diabetic nephropathy development.

Adult↗
PubMed1982

Familial porphyria cutanea tarda: the pattern of porphyrins formed from porphobilinogen by hemolysates.

Porphyria cutanea tarda is thought to result from an inherited deficiency of uroporphyrinogen decarboxylase (EC 4.1.1.37) in some patients. Present methods for determining uroporphyrinogen decarboxylase activity are time consuming, so we examined the pattern of porphyrins formed from porphobilinogen by hemolysates as a possible marker for hereditary porphyria cutanea tarda. After the hemolysates are incubated with porphobilinogen, the porphyrins are converted to their methyl esters and examined by liquid chromatography, with fluorometric detection. The porphyrinic patients examined, and some of their relatives, showed a characteristic pattern of porphyrin production, with high uroporphyrin/coproporphyrin and (uroporphyrin + heptacarboxylic porphyrins)/coproporphyrin ratios, at least partly ascribable to increased uroporphyrinogen I synthetase (EC 4.2.1.8) activity in patients' hemolysates, and also to a relative deficiency of uroporphyrinogen decarboxylase. Examination of the pattern of porphyrins produced from porphobilinogen by hemolysates is a suitable technique for detecting asymptomatic individuals with porphyria cutanea tarda.

Carboxy-Lyases↗
PubMed1981

The use of porphyrins as probes to examine the requirement for hemin in the maintenance of protein synthesis in reticulocyte lysates.

Hemin was compared with other porphyrins for the ability to sustain protein synthesis in reticulocyte lysates and to inhibit the phosphorylation of the alpha subunit of initiation factor 2 (eIF-2 alpha). Iron-containing porphyrins (hemin, mesohemin IX, deuterohemin IX) were found to maintain protein synthesis while iron-deficient porphyrins (protoporphyrin IX, mesoporphyrin IX) were ineffective. All of the porphyrins and metalloporphyrins tested were observed to inhibit phosphorylation of eIF-2 alpha by highly purified hemin-controlled repressor, although at different concentrations. Phosphorylation of eIF-2 alpha was examined in reticulocyte lysates. In the absence of porphyrin, phosphorylation of eIF-2 was rapid and linear for the first 7 min, during which time protein synthesis was inhibited. Both hemin and protoporphyrin IX inhibited phosphorylation of eIF-2 alpha in the lysate during this period; however, hemin sustained protein synthesis whereas protoporphyrin IX did not. Thus, the requirement for iron-containing porphyrins in the maintenance of protein synthesis is not due strictly to an inhibition of the protein kinase activity of the hemin-controlled repressor but involves an alternative, although yet undeciphered, mode of action.

Animals↗
PubMed1995

[The chemistry of porphyrins and their precursors on the heme biosynthetic chain].

There are two ways for numbering the positions of C and N atoms in the porphyrin ring. The Fisher numeration is relatively old styled, but at present, is most widely employed among chemists because of its simpler and easier technique than that of the IUPAC numeration which is more effective in numbering the complicated structures of recent synthetic chemical including recent porphyrin derivatives. Uroporphyrinogen III, Coproporphyrinogen III and Protoporphynogen IX have been described as the porphyrin intermediates in heme biosynthesis. Uroporphyrins, Coproporphyrins and Protoporphyrin IX which are found in blood, urine, feces of either normal or porphyric subjects are their auto-oxidized products and can not be true intermediates for heme biosynthesis except for Protoporphyrin. Delta aminolevulinic acid (ALA), Porphobilinogen (PBG) and Hydroxymethylbilane have been described as the precursors to porphyrin biosynthesis. Besides the recent advance of porphyrin research within the limit of medical fields the pure organic chemistry of porphyrins symbolized by its large electron conjugated system have been unexpectedly developed for the last 20 years, suggesting that its application will quickly be extended to the new fields of macromolecular engineering and polymer electronics.

Aminolevulinic Acid↗
PubMed1995

Endogenous porphyrins in murine skin and transplanted PAM-212 squamous cell carcinoma tissues after injection of delta-aminolevulinic acid.

After intraperitoneal (IP) injection of delta-aminolevulinic acid (ALA), the endogenous porphyrins in murine skin and tumor tissues were determined by a method involving solvent and acid extractions. The results showed that the total amount of porphyrins in the tumor tissues after ALA injection was much higher than that in the skin from the same mice, although the amount of porphyrins in the skin from the ALA-injected mice was higher than that from the saline-injected (control) mice. The porphyrins in the tumor were mostly protoporphyrin and coproporphyrin, with only a small amount of uroporphyrin. The optimum period for porphyrin accumulation in the tumor as well as in the skin was 1 hour after the injection of ALA. As the period was extended to 3 and 6 hours, the amount of porphyrins in these tissues decreased considerably. These findings could be valuable for further application of ALA in the photodynamic therapy of skin cancer.

Aminolevulinic Acid↗
PubMed1994

Fluorescent derivatives of human hemoglobin. Differences in interaction of the porphyrin with the protein between the alpha and beta subunits.

The fluorescence properties of porphyrin were compared in protoporphyrin-protoheme hybrid hemoglobins (Hb) in which the protohemes (Fe) in either the alpha or beta subunits were substituted with protoporphyrin IX, alpha (P)2 beta (Fe)2-Hb and alpha (Fe)2 beta(P)2-Hb, respectively. The fluorescence lifetimes of the porphyrin in these hybrid derivatives are shorter than for the tetra-substituted protoporphyrin Hb, indicating that there is energy transfer from the porphyrin to the heme. The energy transfer resulted in only approximately 20% diminution of donor fluorescence, thereby allowing for the examination by fluorescence of the interaction of porphyrin with a given subunit peptide chain. Fluorescence line-narrowing spectroscopy, a high resolution fluorescence technique that involves laser excitation, produced vibrationally resolved emission spectra in which the zero phonon lines were separated from a broadened background consisting of phonon wings. Resolved spectra were obtained in the temperature range of 5-50 K; above 70 K the spectra were unresolved. By changing the excitation frequency the mean energy of the 0,0 transition, characterizing the separation in energy between the ground and excited states, can be determined. For both derivatives a bimodal distribution was seen, indicating that more than one conformation of molecules was present. The distribution of 0,0 transition energies of the porphyrin in the beta-chain in alpha(Fe)2 beta(P)2-Hb was shifted to lower energy relative to the alpha chain in alpha(P)2 beta(P)2-Hb, whereas the excited state molecules in the two subunits had very little difference in vibrational energy. These data point to the same configuration of the porphyrins in the two sites, but differences in the electric field for the alpha and beta subunits.

Heme↗