James M. Orten

Protein, Nucleotide, and Porphyrin Metabolism

The relation of alcohol to protein, nucleotide, and porphyrin metabolism is obviously a two-way relationship. Thus, not only does alcohol profoundly affect the metabolism of these three major groups of substances but also, in turn, the latter play extremely significant roles in the metabolism of ethanol* itself. This interrelationship forms the basis for the presentation in this chapter.

The combined effects of pregnanolone and porphyrinogenic agents on hepatic delta-aminolevulinic acid synthetase in mice

Abstract The possible role of the 5-beta-H steroid metabolite, pregnanolone, in the regulation of porphyrin-heme biosynthesis has been investigated in a mammalian system, the laboratory mouse. The effect of this steroid metabolite has been assessed by its ability to increase the level and/or activity of delta-aminolevulinic acid synthetase (ALAS) in the livers of mice concomitantly administered a chemical substance which increases porphyrin-neme formation. The porphyrinogenic agents employed were allylisopropylacetamide (AIA) and 1,4-dihydro-3,5-dicarbethoxy-2,4,6-trimethylpyridine (DDC). In additional experiments, the hypocholesterolemic agent, trans-1,4-bis-(2-chlorobenzylaminomethyl)-cyclohexane dihydrochloride, AY-9944, with and without the porphyrinogenic agent and with and without pregnanolone, was used. In all experiments, the administration of pregnanolone along with the porphyrinogenic agent, AIA or DDC, resulted in a significantly greater increase in hepatic ALAS level/activity than that obtained with the porphyrinogenic agent alone. The administration of the hypocholesterolemic agent, AY-9944, prevented the induction of ALAS by AIA. The simultaneous injection of pregnanolone, however, reversed the inhibitory effect of AY-9944, the specific activity of hepatic ALAS increasing toward the high level induced by AIA alone. An interesting, as yet unexplained, inhibitory effect on hepatic ALAS levels/activity was observed following the administration of the solvents, propylene glycol or ethanol, in control experiments. The present results thus suggest that the 5-beta-H steroid metabolite, pregnanolone, may be a regulatory factor in porphyrin-heme formation in a mammalian species as was indicated in earlier studies for an avian system.

A micromethod for silica-gel column chromatography of urinary organic acids

Abstract Silica-gel column Chromatographic method for the quantitative determination of micro-quantities of 12 different, physiologically most important, organic acids in mixtures, as well as in human and rat urine samples, is described. This method is simple, accurate, rapid, and has a high degree of sensitivity. It yields a high percentage of recovery and the results are reproducible. The identity of the acids separated by this technique has been repeatedly confirmed by paper chromatography; known pure acids were compared with those eluted from the silica-gel column used in this method.

Hematuria Following Administration of Ethanol

Hematuria, with some erythrocytes also appearing in the urine, was observed in male albino rats given 20 percent and 40 percent ethanol in lieu of drinking water for several weeks. However, the amounts of hemoglobin in the blood of the treated group did not change relative to those of the control group; this finding indicates that the degree of hematuria was not sufficient to produce an anemia.

The regulation of porphyrin-heme biosynthesis: the effects of certain steroids and other porphyrin-inducing agents in different in vitro systems.

Abstract The effects of certain steroids, sedormid, and a barbiturate on the biosynthesis of porphyrins were studied in several in vitr systems using either avian erythrocytes, rat liver homogenates, or bovine liver acetone powder as the porphyrin-synthesizing system. No direct stimulatory or inhibitory effect was observed under the conditions employed. The present results thus show that in vitro systems lacking (avian erythrocytes) or having limited capacity (livers of adult animals) for the induction of δ-aminolevulinic acid synthetase exhibit little or no response to the in vivo porphyria-inducing agents studied. In contrast, in vitro systems having the ability of ALAS induction (bone marrow cells, embryonic liver cells) show increased porphyrin formation upon treatment with these same chemical agents. The present results are in accord with the current concept that the effect of these substances on porphyrinogenesis is indirect apparently by way of the induction of the key enzyme of the porphyrin biosynthetic pathway, δ-aminolevulinic acid synthetase. Impairment of terminal cellular oxidation by the inhibition of NADH oxidase activity, resulting in lower cellular ATP levels, may be a common, primary factor involved in inducing the biosynthesis of ALAS by the chemical agents employed.

The effects of certain inorganic ions on in vitro porphyrin-heme formation☆

Abstract The effects of several inorganic ions (Fe, Cu, Co, Zn, As, Mo, U) on porphyrin-heme formation were studied in two in vitro systems, avian erythrocytes and bovine liver “acetone powder.” No direct effects of molybdenum, arsenic, uranium and probably zinc were observed. Ferrous ion gave the expected increase in heme formation at the expense of protoporphyrin. As might be expected EDTA decreased heme formation but had no significant effect on porphyrin level. Both copper and cobalt depressed porphyrin formation in bovine liver acetone powder preparations which were dosage level dependent. However, in avian erythrocytes, copper increased the formation of heme, apparently at the expense of porphyrin intermediates, presumably by increasing the utilization of iron. The alleged in vivo hemopoietic effects of the “trace elements,” cobalt, zinc, molybdenum, arsenic and uranium, thus apparently involve factors or mechanisms having some indirect relation to porphyrin-heme formation.

The Effects of Certain Hypocholesterolemic Agents on Hepatic Delta-Aminolevulinic Acid Synthetase Levels in Mice

Summary The effects of the hypocholesterolemic agents, trans-1,4-bis- (2-chloro-benzylaminomethyl) -cyclohexane dihy dro-chloride (AY9944) and beta-benzalbutyric acid (BBB), on the level (activity) of delta-aminolevulinic acid synthetase (ALAS) in the mitochondria of livers of mice injected with certain porphyrinogenic compounds were studied. The porphyrinogenic agents employed were allylisopropylacetamide (AIA) and 3,5-dicarbethoxy-1,4-dihydro-2,4,6-trimethylpyridine (DDC). All substances were administered parenterally. Both AY-9944 and BBB injections prevented the increase in hepatic mitochondrial ALA-synthetase levels which otherwise follow the injection of AIA or DDC. AY-9944 administration also produced a consistent decrease in serum cholesterol levels. These data suggest that a decrease in the hepatic steroid “pool” and presumably that of 5-beta-H-steroid metabolites, as reflected by the serum cholesterol level, is associated with the observed decrease in hepatic mitochondrial ALAS. The present data thus support, by an entirely different approach, other evidence implicating steroid metabolites in the regulation of porphyrin-heme biosynthesis in a mammalian species.

A Comparison of Porphyrin Synthesis in Certain Tissues from Normal and Anemic Dogs Some Observations on the in Vivo Control of Porphyrinogeneis

Summary The ability of certain tissues from anemic dogs to form copro- and protoporphyrins from glycine and acetate or from delta-aminolevulinic acid (ALA) has been compared with that of tissues from normal control dogs. None of the tissues studied formed porphyrins from glycine and acetate. However, tissues from normal dogs formed porphyrins from ALA, and in decreasing order of activity, liver, spleen, kidney, and heart. The tissues from the phenylhydrazine-treated dogs showed significantly less copro- and protoporphyrin formation than did those of the control dogs. Porphyrin synthesis in the spleen was especially decreased. In contrast, all tissues from the group made anemic by bleeding showed increased porphyrinogenesis as compared with the controls. The same results were obtained in dogs similarly treated but administered added iron. It is suggested that the decrease of porphyrin biosynthesis observed in the tissues from the phenylhy-drazine-treated dogs may result from an in vivo “feedback” inhibition by coordinate repression by heme or possibly a related metabolite. The increased porphyrinogenesis observed in the tissues of the dogs made anemic by bleeding may be related, either directly or indirectly, to erythropoietin or to some other hemopoietic factor.

Role of a plasma factor in porphyrin biosynthesis.

Summary Evidence is presented which indicates that there is present in the plasma of normal dogs a factor, possibly some type of plasma protein or a related substance, which inhibits in vitro biosynthesis of porphyrins from ALA. The amount of activity of this factor is decreased in the plasma of anemic phenylhydrazine-treated dogs. It is suggested that this plasma inhibitory factor may play a physiological role in regulating porphyrino-genesis.

Fumaric Acid Salts as Hydrogogue Cathartics.

Summary The laxative action of sodium, magnesium, and calcium fumarates has been compared with that of sodium potassium tartrate in 143 chronically constipated patients. The fumarates have been found as satisfactory as Rochelle Salts as a laxative agent.