Quantification of urinary zwitterionic organic acids using weak-anion exchange chromatography with tandem MS detection

A rapid and accurate quantitative method was developed and validated for the analysis of four urinary organic acids with nitrogen containing functional groups, formiminoglutamic acid (FIGLU), pyroglutamic acid (PYRGLU), 5-hydroxyindoleacetic acid (5-HIAA), and 2-methylhippuric acid (2-METHIP) by liquid chromatography tandem mass spectrometry (LC/MS/MS). The chromatography was developed using a weak anion-exchange amino column that provided mixed-mode retention of the analytes. The elution gradient relied on changes in mobile phase pH over a concave gradient, without the use of counter-ions or concentrated salt buffers. A simple sample preparation was used, only requiring the dilution of urine prior to instrumental analysis. The method was validated based on linearity (r2>or=0.995), accuracy (85-115%), precision (C.V.<12%), sample preparation stability (<or=5%, 72 h), and established patient ranges. The method was found to be both efficient and accurate for the analysis of urinary zwitterionic organic acids.

[Megaloblastic anemia: rapid and economical study]

The diagnosis of megaloblastic anaemias caused by cobalamine or folate deficiency are still difficult. The dosage of these two substances help to differenciate between both carencies, but it is not determinant of any of them and is an expensive method. Homocisteinuria (HC), methylmalonuria (MMA) and formiminoglutamic acid (FIGLU) are cheap tests which could help in the differential diagnosis, if they are used properly. We report 62 patients to whom we made these test simultaneously. All of the patients received 10 micrograms of vit B12 and after 72 hours, 1 mg/day of folic acid (for 3 days). In both cases waiting for the increase of reticulocytyes up to 150 x 10(9)/L as a form of therapeutic test of diagnosis. By this simple way we have detected 97.9% of specificity for cobalamin deficiency of the MMA test, and only 4.2% for HC. This last test had increased its specificity up to 91.6% in association with the negative FIGLU test. We have also found a high specificity (92.3%) for FIGLU due to the detection of folate deficiency, in opposition with other authors who had described it as low as 50%. We have also compared the costs of the 3 tests with the dosage of cobalamine and folate, and we have found that the formers are 11 times less expensive than the last ones.

Effect of folate supplementation on clinical chemistry and hematologic changes related to bidisomide administration in the rat

In a chronic toxicity study in the rat, bidisomide administered as a dietary admixture produced a dose-related lowering of reticulocytes and leucocytes. Plasma alanine aminotransferase activity was increased at 300 mg/kg and decreased at 900 mg/kg. The potential mechanisms of these effects were investigated by comparing the responses in groups of male Sprague-Dawley rats receiving a control diet, or 300 or 1200 mg/kg/day bidisomide. Subsets of these groups were co-treated subcutaneously with folinic acid or with a vitamin B1, B6, B12 complex. Subsets of control and 300 mg/kg groups were maintained on a 20-25% feed restriction regimen for 3 months, to mimic the depression in body weight gain observed in animals receiving 1200 mg/kg. Body weight gains were significantly reduced at 1200 mg/kg and in all feed-restricted animals. Plasma and liver alanine aminotransferase (ALT) and plasma aspartate aminotransferase (AST) levels were also reduced at this dose level. At 300 mg/kg, plasma transaminases, glutamate dehydrogenase (GLDH) and sorbitol dehydrogenase (SDH) activities were increased. These changes were prevented in animals receiving folinic acid supplementation. Plasma glucose, triglycerides, and unsaturated and total iron binding capacities were decreased, while plasma iron levels tended to increase, mainly at the high dose. Vitamin supplementation prevented a decrease in reticulocyte counts at 300 mg/kg. Bidisomide increased urinary formimino-glutamic acid (FIGLU) excretion but did not affect methylmalonic acid (MMA) or taurine excretion. The effect on FIGLU at 1200 mg/kg was prevented by folinic acid co-treatment. Absolute liver weight was lowered at both dose levels and in feed-restricted animals. However, the relative liver weights were unaffected. Thymidine kinase and thymidylate synthase activity of the bone marrow cells were not altered by the bidisomide treatment. Except for the increase in plasma transaminase, GLDH and SDH levels at 300 mg/kg, changes in clinical chemistry parameters are considered to result mainly from nutritional restrictions. Changes in hematologic parameters appear to be related to the combination of decreased feed consumption (leukocytes) and decreased availability or utilization of folates (reticulocytes). This alteration, however, did not affect DNA synthesis in bone marrow. The prevention by folinic acid, but not by feed restriction, of the elevation of liver enzymes at 300 mg/kg is an intriguing, yet unexplained finding. There was no evidence that bidisomide affected B6 and B12 availability.

Cobalamin-dependent metabolism in chronic myelogenous leukemia determined by deoxyuridine suppression test and the formiminoglutamic acid and methylmalonate excretion in urine

The cobalamin metabolism in chronic myelogenous leukemia (CML) was evaluated in 18 newly diagnosed and untreated patients by formiminoglutamic acid (FiGlu) and methyl malonic acid excretion (MMA) tests. A deoxyuridine (dU) suppression test of bone marrow cells was compared in patients with acute myelogenous leukemia (N = 5), myelodysplastic disease (N = 3), untreated pernicious anemia (N = 16), folate deficiency (N = 7), and a hospital reference group without signs of cobalamin or folate deficiency (N = 22). All had normal MMA excretion but 3 of 15 patients had increased FiGlu excretion. In vitro thymidine uptake in bone marrow cells of CML patients were lower (mean 40 fmol/106 cells) than pernicious anemia patients (115 fmol/106 cells). Methotrexate (MTX) increased the uptake in all cases. Addition of formyl-THF, methyltetrahydrofolate (methyl-THF), and pteroylglutamic acid (PGA) tended to normalize the effect of MTX. In pernicious anemia methyl-THF only decreased the uptake in combination with CN-Cbl. dU suppression values were significantly higher (6.3%) in CML than in the reference group (4.4%), but significantly lower than in pernicious anemia (41.6%) and folate deficiency (28.5%). The dU suppression values in bone marrow cells of CML patients correlated significantly with the transferrin saturation. In buffy coat cells dU suppression values were even higher (9.3%) than in bone marrow cells of the same CML patients. Addition of folate forms and CN-Cbl did not change the dU suppression values in CML, as it did in pernicious anemia. MTX increased dU suppression values significantly in all patients, but more in CML (64.5%) than in pernicious anemia (48.6%) and controls (49.8%). The MTX effect was to some extent neutralized by folate analogues with formyl-THF as the most effective followed by methyl-THF and lastly PGA. Methyl-THF also neutralized MTX in pernicious anemia, but its effect was certainly enhanced by addition of CN-Cbl. Thymidine uptake and dU suppression patterns were not significantly changed in CML after treatment with busulfan for 1 week or in accelerated phase. We concluded that signs of cobalamin or folate deficiency (apart from one patient) cannot be demonstrated in untreated CML. However, dU suppression was significantly increased and more so in circulating myeloid cells than in bone marrow. This indicates a deranged metabolism of deoxynucleotides which is independent of cobalamin and folates, and a difference between bone marrow cells and circulating cells. dU suppression is a valuable indicator of cobalamin deficiency.(ABSTRACT TRUNCATED AT 400 WORDS)

Inter-relationships between single carbon units' metabolism and resting energy expenditure in weight-losing patients with small cell lung cancer. Effects of methionine supply and chemotherapy

The one-carbon unit metabolism was investigated in 8 weight-losing patients with small cell carcinoma of the lung (SCLC). At diagnosis, 6 of the 8 patients had elevated formiminoglutamic acid (FIGLU) excretion after a histidine load, suggesting a lack of one-carbon units. In accordance, a significant decrease of FIGLU excretion was observed in the patients after oral administration of DL-methionine for 4 days. The elevated FIGLU excretion was positively correlated to weight loss prior to diagnosis and negatively correlated to serum albumin at time of diagnosis. After 3 months of combination chemotherapy, FIGLU excretion was reduced in all patients except 1, who had progressive disease. Despite the elevated FIGLU excretions, all patients had normal blood folate levels. The resting energy expenditure (REE) was recorded in 7 patients, and a significant, positive correlation was observed between pretreatment FIGLU excretion and REE, although the REE measured in this group of patients was within the normal range. These data demonstrate an increased demand of "active" one-carbon units in energy consumption in a group of weight-losing cancer patients. The one-carbon unit deficit was reconditioned by oral administration of the one-carbon unit donor DL-methionine.

Vitamin B12 and folate status in rats after chronic administration of ethanol and acute exposure to nitrous oxide

The chronic administration of ethanol or brief exposure to nitrous oxide (N2O) decreases the activity of hepatic methionine synthase and disrupts normal metabolic processes that require folate and vitamin B12. This combination of drugs has clinical relevance since alcoholic patients often require surgery and receive N2O as a component of their anesthetic. To assess this clinical problem using a rodent model, rats were given a liquid ethanol diet (35% of calories as ethanol) and control rats were pair-fed a liquid diet with carbohydrate substituting for the caloric content of ethanol. After receiving liquid diets for 6 weeks, rats were exposed to 60% N2O/40% O2 for 6 hr. Urinary excretions of formic acid and formiminoglutamic acid (FIGLU) were used as indirect markers of folate status. In both the ethanol-fed and control groups, excretion of formic acid and FIGLU markedly increased the first day after N2O and returned towards background values by the second day after N2O exposure. Ethanol treatment alone decreased methionine synthase activities in liver, but not kidney or brain. Exposure to N2O further decreased methionine synthase activities, and recovery of methionine synthase activity after N2O occurred over a period of 4 days at the same rate in both the ethanol-fed and control groups. Ethanol treatment for 6 weeks combined with acute exposure to N2O did not deplete the rats of vitamin B12 in blood, liver, kidney, or brain. We conclude that in this animal model, chronic treatment with ethanol does not markedly exacerbate the disturbances in folate/vitamin B12 metabolism caused by brief exposure to N2O.

Vitamin B-12 and folate function in chronic alcoholic men with peripheral neuropathy and encephalopathy

Forty-six male alcoholics hospitalized with polyneuropathy or intellectual impairment were studied after at least 2 wk of alcohol abstention. Neurological evaluation included neurophysiological examination of the sural nerve and tibial nerve, neurophysiological examinations, and CT-scanning of the brain. Alcohol and vitamin intakes were quantified by the interview method. Vitamin B-12 and folate status included examinations of peripheral blood and bone marrow aspirate, plasma vitamin B-12, plasma and erythrocyte folate, formiminoglutamic acid excretion test (FiGlu), methylmalonic acid excretion, and deoxyuridine suppression test (dU) on phytohemagglutinin-stimulated peripheral lymphocytes. The liver function was assessed by galactose elimination capacity and plasma clearance of antipyrine. There was no hematological sign of folate or vitamin B-12 deficiency. About 8% had low plasma folate, while neither erythrocyte folate nor plasma vitamin B-12 were decreased. However, half of the patients had functional folate deficiency as determined by abnormal FiGlu or dU. Compared to the remaining patients, those with abnormal FiGlu or dU had significantly more abnormal neurophysiological tests, and lower folate intake. There was no correlation between FiGlu or dU and the quantitative liver function tests. It is concluded that 1) folate deficiency may contribute to the development of alcoholic polyneuropathy, 2) the classical parameters for folate deficiency (blood concentrations, peripheral blood, and bone marrow examinations) are not reliable in diagnosing folate deficiency and 3) functional tests like FiGlu and dU are necessary to diagnose folate deficiency in alcoholics.

Folate deficiency in rats fed diets containing free amino acids or intact proteins

Development of folate deficiency (FD) was evaluated in weanling rats fed diets containing mixtures of free amino acids or of vitamin-free casein and gelatin as sources of dietary nitrogen. FD could be produced in 21 d with amino acid diets that promoted maximum growth rate, were completely devoid of folate and contained 1% succinylsulfathiazole. Growth retardation and blood dyscrasia associated with FD could not be demonstrated in rats fed diets containing casein and gelatin as nitrogen sources because the vitamin-free casein contained low but measurable levels of folate. The most effective protocol to produce experimental FD in rats is to feed a folate-free diet that otherwise supports maximum growth in young animals. Additional modifications such as use of methotrexate or amino acid-imbalanced or protein-deficient diets are unnecessary.

Erythrocyte formimino glutamate transferase in FIGLU aciduria

A patient is described who presented at an early age with failure to thrive and vomiting, and had a gross excretion of formimino glutamic acid. She had normal concentration of serum folate and vitamin B12, and no haematological abnormalities, and is not mentally retarded. The Michaelis constant for erythrocyte formimino glutamate transferase was in the normal range, but the enzyme behaves differently from that from reference subjects with respect to inhibitors and activators.

Perturbation of methionine metabolism in sheep with nitrous-oxide-induced inactivation of cobalamin

Exposure of sheep to 36% nitrous oxide for 8 days (2-hr per day) led to 90%, 82% and 74% inhibition of 5-methyltetrahydrofolate-homocysteine methyltransferase in the liver, heart and brain, respectively, while there was no significant decrease in the activity of methylmalonyl-CoA mutase. There was also no change of betaine-homocysteine methyltransferase activity. The level of plasma methionine in nitrous-oxide-exposed sheep fell to 30% of its initial value. S-Adenosylmethionine level was reduced to 50% of the control value in the liver, and was also significantly decreased in the heart, but not in the brain. Excretion of formiminoglutamic acid and homocystine was also observed in the urine of sheep exposed to nitrous oxide. These results demonstrate that inhibition of 5-methyltetrahydrofolate-homocysteine methyltransferase causes a pronounced perturbation of methionine metabolism in sheep, suggesting that dietary methionine plus methionine synthesized from the methyl groups of betaine are not sufficient to meet the methyl needs for biological methylation reactions in this species and, in turn, emphasizing the role of 5-methyltetrahydrofolate-homocysteine methyltransferase in methionine synthesis in the sheep.

Effect of methionine on in vivo histidine metabolism in rats

Experiments were conducted to examine the effects of methionine supplementation on histidine metabolism in rats. All animals were fed 10% casein diets with a methionine content of either 0.6 or 1.1%. Experiments in which the animals were fed their diets containing an additional 1% histidine ad libitum for at least 10 days revealed that methionine-supplemented animals had a 49% reduction of plasma histidine and an 80% reduction in urinary excretion of formiminoglutamic acid (FIGLU) on day 10. This effect was not observed on day 5. In subsequent experiments rats were fed the control or test diet ad libitum prior to receiving their diets, containing a histidine load, by force-feeding. When a 100-mg histidine load was given on day 5, 24-hour urinary FIGLU excretion was 83% lower in methionine-supplemented animals. When rats were force-fed a 75-mg [ring-2-14C]histidine load on day 10, those receiving supplemental methionine oxidized 21% more of the histidine label to 14CO2 and excreted 61% less of the dose as urinary FIGLU in 24 hours. The activities of histidase and urocanase were unaffected by the methionine supplement. The results suggest that dietary methionine supplementation enhances the in vivo catabolism of histidine by stimulating one-carbon metabolism. Delivery of the methionine supplement by ad libitum feeding requires at least 5 days for this effect to be achieved.

Increased urinary excretion of formiminoglutamic acid in nitrous-oxide-treated rats and its reduction by methionine

Inhalation of nitrous oxide oxidises cob(I)alamin and inactivates methionine synthetase of which cobalamin is a co-enzyme. The biochemical changes in the rat following exposure to nitrous oxide resemble in some detail the changes present in patients with untreated pernicious anemia due to deficiency of cobalamin. There is a marked increase in the excretion of formiminoglutamic acid in the urine following exposure to nitrous oxide. A significant decrease is produced, while on N2O, by giving methionine. The explanation for these findings is discussed in the light of recent data on the effects of cobalamin inactivation.

Skin histidase activity and urine formiminoglutamic acid (FIGLU) in patients with histidinemia found by screening newborn infants

Skin histidase activities and urine formiminoglutamic acid (FIGLU) levels were measured in 20 patients with histidinemia, identified by Guthrie's screening method, and their family members as well as control subjects. There was a significant positive correlation between skin histidase activities and the amounts of urine FIGLU. Although the difference of skin histidase activity and the amount of urinary FIGLU was significant between any two of the three groups (i.e. controls, parents and patients; p less than 0.005), these levels ranged widely and a considerable number of the cases overlapped among groups. When a discriminant function was computed to obtain the minimum probability of misclassification between the groups using the above two parameters, a better segregation was observed. However, even though the number of misclassifications decreased, the overlapping cases were still present, especially between the parent and patient groups. It is concluded that either skin histidase activity, urine FIGLU, or both, can be used as genetic markers of the disease to a large but still limited extent.

Enhancement of histidine and one-carbon metabolism in rats fed high levels of retinol

Histidine metabolism was studied in rats fed 10% casein diets supplemented with 1000 IU of retinol/g concurrent with or previous to exposure to high levels of dietary histidine (1% or 2%). When a retinol-supplemented 10% casein + 1% histidine diet was fed ad libitum for 21 days, urinary excretion of formiminoglutamic acid (FIGLU) was decreased by 50-70% over the entire period and plasma histidine was reduced by 30-70% for 16 days compared to rats receiving 10% casein + 1% histidine with normal levels of retinol. Rats pretreated for 10 days with a 10% casein diet supplemented with high levels of retinol oxidized 30% more L-[ring-2-14C]histidine to 14CO2 and excreted 76% less of the administered dose as urinary FIGLU compared to control rats not pretreated with high levels of retinol. Depression in growth due to supplementation of a 10% casein diet with 1% histidine were also partially alleviated in rats that were first pretreated with retinol. Activities of histidase, urocanase, and formiminoglutamic acid formiminotransferase (FIGLU transferase) were unaffected by retinol supplementation. The results suggest that retinol supplementation enhances histidine catabolism by exerting a change on one-carbon metabolism.

Oral contraceptives: effect of folate and vitamin B12 metabolism

Women who use oral contraceptives have impaired folate metabolism as shown by slightly but significantly lower levels of folate in the serum and the erythrocytes and an increased urinary excretion of formiminoglutamic acid. The vitamin B12 level in their serum is also significantly lower than that of control groups. However, there is no evidence of tissue depletion of vitamin B12 associated with the use of oral contraceptives. The causes and clinical significance of the impairment of folate and vitamin B12 metabolism in these women is discussed in this review of the literature. Clinicians are advised to ensure that women who shop taking "the pill" because they wish to conceive have adequate folate stores before becoming pregnant.

A case of formiminoglutamic aciduria. Clinical and biochemical studies

We describe a boy who excreted massive amounts of formiminoglutamic acid and hydantoin-5-propionic acid in his urine. He was mildly mentally retarded and epileptic, whereas his twin-brother was completely normal. Loading with L-histidine enhanced the excretion of both metabolites. Treatment was attempted with high doses of folic acid and methionine, but both were without effect on the excretion levels.

Formiminoglutamic aciduria in a slightly retarded boy with chronic obstructive lung disease

A 2-year-old boy excreted massive amounts of formiminoglutamic acid in urine. The substance was identified as authentic formiminoglutamic acid by two-dimensional thin-layer chromatography, column chromatography and enzymatic determination. After alkaline hydrolysis the substance was converted to glutamic acid. Serum amino acid concentrations were normal. The patient had normal serum and erythrocyte folate levels. The red blood cell picture was normal. The leukocytes showed slight hypersegmentation. From the age of 3 months he exhibited recurrent otitis media and severe pulmonary infections. He had a peculiar narrow-headed look and marked universal hypotonia. The mental development was slightly retarded. Glutamate formiminotransferase deficiency is postulated. The findings lend support to the theory of glutamate formiminotransferase deficiency being a rather benign disorder of metabolism.

A liver urocanase deficiency

Two sisters with a rare inborn error of histidine metabolism resulting from urocanase deficiency are being presented. The more common form of familial histidinemia due to histidase deficiency is excluded. The urocanase deficiency is proven by demonstrating increased excretion of metabolites of the product of the urocanase enzyme action. Further, the strongest evidence for the urocanase defect rests on the demonstration of urocanase deficiency and normal histidase activity in liver.

Metabolic responses of folic acid and related compounds to thyroxine in rats

This study deals with the effects of thyroidectomy and feeding thyroid powder on histidine and folic acid metabolism. Normal rats maintained on a soy protein diet, low in methionine but supplemented with vitamin B-12, oxidize approx. 10% of an injected dose of [2-14C]histidine in 3 h and excrete low levels of formiminoglutamic acid. Addition of methionine increases histidine oxidation to approx. 20%. The feeding of thyroid powder or the injection of high levels of thyroxine decreases histidine oxidation and increases formiminoglutamic acid excretion. Surgical thyroidectomy at weaning increases histidine oxidation to approx. 45% and, thus, resembles the effect of methionine in promoting histidine oxidation and decreasing formiminoglutamic acid excretion. The feeding of methionine to the thyroidectomized animal further increases histidine oxidation to 65%. The distribution of folate forms in the liver was determined by column chromatography following administration of a dose of tritiated folic acid. In the normal animal, tetrahydrofolate accounts for 38% of the total folate present. The feeding of methionine increases this to 48%, which is consistent with the observed increase in histidine metabolism. Thyroidectomy increases the percentage of tetrahydrofolate to 63% and the feeding of methionine further increases it to 68%. The percentage of tetrahydrofolate relative to total folate is in proportion to the observed rate of histidine metabolism. The action of thyroidectomy in increasing histidine oxidation may be accounted for by its effect in increasing the proportion of tetrahydrofolate.

Utilization of administered folacin derivatives by rats fed a diet low in methionine and folacin

Rats fed a basal diet low in folacin and methionine or the basal supplemented with 1.5% methionine were injected with either tetrahydrofolic acid, 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, or folic acid. The level of formiminoglutamic acid (FIGLU) excretion was used as an indicator of the animal's metabolically available folacin. Rats fed the basal diet had no decline in FIGLU excretion after dosing. The methionine-supplemented group had significant decreases in FIGLU excretion after dosing with the folacin derivatives. When rats eating the basal diet were dosed with methionine or homocysteine, FIGLU excretions were again decreased.

Bone marrow studies in myelomatosis

The percentage of fat-cell areas in bone marrow particles from 22 patients with untreated myelomatosis was estimated. In only 1 patient was the mean fat cell area below 25% of the bone marrow area measured. A negative correlation was found between the area of fat cells and plasma cells, indicating a displacement of the fat cell area by the plasma cells. 28% of the patients had empty bone marrow deposits of iron. However, based on a normal iron saturation of S-transferrin and a normal sideroblast count in the bone marrow, the supply of iron to the erythropoiesis was considered sufficient. All patients but one had normoblastic bone marrows. Using a deoxyuridine suppression test in 10 patients, no biochemical defect could be demonstrated. To judge from the correlation coefficient a minor degree (9-14%) of the variation in Hb values could be predicted from the cellularity in the bone marrow while a major degree (70%) could be predicted from the renal glomerular filtration rate. The results do not support a displacement of blood-forming elements, iron deficiency, vitamin B12 or folic acid deficiency to be of general significance in the pathogenesis of anaemia, but agrees with a causal relationship between anaemia and renal failure.

Increased concentration of transcobalamin I in a patient with metastatic carcinoma of the breast

A patient with metastatic carcinoma of the breast and increased plasma cobalamin binding capacity (about 50 nmol/1) is described. The binding protein was identified as transcobalamin I (TCI) by DEAE cellulose ion-exchange chromatography, Sephadex G200 gel filtration and agar gel electrophoresis. Although the total plasma cobalamin concentration (about 20 nmol/1) was elevated, the patient complained of neurological symptoms in accordance with a functional vitamin B12 deficiency. Hence, an inactivation of the coenzyme is suggested by the demonstration of considerable amounts of 5'-deoxyadenosylcobalamin bound to the plasma TCI. Both urinary excretion of FIGLU and methylmalonic acid were within the reference ranges. Reported cases of increased cobalamin binding in patients with nonhaematological malignancy are reviewed. Further investigations to characterize the function of the cobalamin dependent metabolic pathways are necessary to determine the importance of the increased transcobalamin binding in these patients.

Blood and liver folacin activity, formiminoglutamic acid excretion, growth and hematology in guinea pigs fed a folacin deficient diet with and without sulfonamides

Dietary folacin deficiency in the presence and absence of dietary sulfonamides was studied in the guinea pig for the purpose of relating the growth and hematologic effects of folacin deficiency to tissue and biochemical changes. Six-week old female guinea pigs fed control and folacin deficient diets with and without 0.1% sulfonamides for 6 to 7 weeks. Growth was significantly reduced in both groups fed the folacin deficient diets, and 25% of all deficient animals died. Macrocytic anemia was not present, but reduced leukocyte numbers were observed in folacin deficiency. Plasma and red blood cell folacin activities were reduced by about 50% in deficient guinea pigs in the presence and absence of dietary sulfonamides. Both liver total folacin activity and urinary formiminoglutamic acid excretion were not significantly altered by the degree of folacin deficiency obtained in this study.

Effect of folic acid deficiency on pregnant rats and their offspring

Two groups of 63-day-old female Wistar rats were fed a folic acid deficient diet, based on 20% of vitamin-free casein and containing 1% of succinylsulfathiazole, for 5 weeks (group A) and 9 weeks (group B) before being bred, and the same diet was continued through pregnancy and lactation. Three out of eleven (21.3%) and three out of seven (42.9%) rats in groups A and B, respectively, resorbed completely, while no control rat resorbed. No pups from group B survived to weaning. Both groups (A and B) showed depressed feed consumption (although the effect in group A rats was small) and weight gains and increased formiminoglutamic acid excretion in the urine during gestation, and low serum folic acid by the end of lactation. A study of blood components in group A rats revealed leucopenia, granulocytopenia, and increased reticulocyte count. While no congenital deformities were observed in pups from deficient dams, group A and group B dams in contrast to controls produced smaller sized litters with lower birth weights and poor survival rate. Surviving pups from group A dams had decreased weaning weights with significantly lower brain weights and brain DNA per gram of tissue.

A methionine-reversible folate deficiency in rats following the acute administration of diethylnitrosamine and alpha-naphthylisothiocyanate

Acute doses of the hepatotoxic agents diethylnitrosamine (DEN) and alpha-naphthylisothiocyanate (ANIT) to young adult male rats led to the production of a folate deficiency as determined by an elevated urinary excretion of formiminoglutamic acid (FIGLU) 2 to 4 days following administration of the compounds. High dietary levels of methionine significantly reduced the elevated levels of FIGLU produced by the 2 chemicals. Dietary folate had no significant effect on the excretion of urinary FIGLU. Although the hepatic levels of S-adenosylmethionine (SAM) were significantly increased in rats fed the high dietary levels of methionine, an acute dose of DEN did not depress the hepatic levels of SAM. The results indicate that the methyl-reversible folate deficiency caused by hepatotoxic agents is not the direct consequence of altered hepatic levels of SAM.

Effect of methionine on the metabolism of formate and histidine by rats fed folate/vitamin B-12-methionine-deficient diet

The metabolism of formate and histidine were compared in rats and in perfused livers of rats on diets deficient in vitamin B-12, methionine, and folic acid. Excretion of formate and formiminoglutamic acid, and the oxidation of [2-14C]histidine and [14C]formate to 14CO2 were measured. Liver folate levels decreased to 40% of normal on the vitamin B-12- and methionine-deficient diets but the rate of oxidation of histidine to CO2 in the whole animal decreased to 15% of normal. This indicated a reduction in the metabolic activity of the liver folates in vitamin B-12deficiency. Comparison of formate and histidine catabolism in folic acid deficiency showed that the oxidation of histine was decreased to 5% of normal but formate oxidation was decreased to only 30% of normal. This indicates that 25% of formate oxidation normally proceeds by a non-folate-dependent pathway.

Urinary formiminoglutamate in man. Normal values related to sex and age. Effects of low calorie intake and alcohol consumption

A modification of the enzymic method of Tabor and Wyngarden for formiminoglutamate (FIGLU) estimation in urine is described. Alkaline degradation of FIGLU in blanks enhanced the sensitivity of the method. FIGLU excretion in 94 healthy persons indicated a sex and age dependence. Short term calorie restriction or fasting led to a decrease of FIGLU excretion while acute alcohol intoxication or chronic alcohol administration were accompanied by enhanced FIGLU excretion. It is suggested that decreased FIGLU excretion was due to histidine deficiency.

Mobilization of folate from liver into blood stream following histidine injection in rats

A marked reticulocyte response following intraperitoneal injections of histidine monohydrochloride was observed in rats which were fed on a folate-free diet immediately after weaning for a period of 20 days or more. This finding was taken as an evidence for mobilization of folate stored in the liver into blood stream following histidine injection.

Hydantoin-5-propionic aciduria in folic acid nondependent formiminoglutamic aciduria observed in two siblings

Hydantion-5-propionic acid was detected in massive amounts in the urine of two previously described sisters with folic acid nondependent formiminoglutamic aciduria. HPA was identified rigorously, e.g. by gas chromatography-mass spectrometry, and was measured quantitatively by selected ion monitoring (mass fragmentography) using deuterated HPA as internal standard. Before histidine loading, both girls with the postulated formiminotransferase deficiency excreted an amount of HPA more than 50 times greater than the control subjects. After histidine ingestion, HPA excretion was still doubled or tripled. With the exception of the father, the values for the other members of the family also markedly exceeded the normal range and were of the same order of magnitude as in folate deficiency. Measurement of HPA excretion in urine seems to be a valuable supplement or alternative to the enzymatic FIGu test for the detection of general or functional folate deficiency or impaired folate utilization and it will be indispensable for the detection of (as yet unknown) 4-imidazolone-5-propionic acid hydrolase deficiency.