Erythrocyte Glutamic-pyruvic Transaminase Research Articles

Current prevalence of vitamin B 6 deficiency in hemodialysis and peritoneal dialysis patients

Objective: To describe the current prevalence of vitamin B 6 deficiency based on erythrocyte glutamic pyruvic transaminase (EGPT) index in dialysis patients. Design: Cross-sectional descriptive study. Setting: Four ambulatory clinical sites, including two hemodialysis clinics, one outpatient clinic for peritoneal dialysis patients, and one site providing care to both hemodialysis and peritoneal dialysis patients (a university-affiliated medical center). Patients: One hundred five adult dialysis patients (63 men and 42 women; ages 21 to 84 years) participated in this study. The ethnic makeup of the patient population in this study is as follows: 76 white, 24 black, and 5 patients of unknown ethnicity. Seventy-five percent were hemodialysis patients, and 25% were peritoneal dialysis patients. Intervention: Vitamin B6 status was measured with the EGPT index. Assessment of dietary intake during the preceding 3 months was conducted with a standardized food frequency questionnaire. Body composition was estimated with skinfold thickness measures. Main outcome measure: Fifteen (14%) patients were found to be vitamin B 6 deficient on the basis of an abnormal EGPT index of ≥1.25. Vitamin B6 supplementation, dietary vitamin B 6 or protein intake, type of dialysis, medication usage, gender, age, and ethnic group were not associated with or predictive of vitamin B6 status. Diabetes comorbidity and abnormal EGPT index were significantly associated ( P < .02), and logistic regression analysis revealed diabetes to be a significant independent predictor of vitamin B 6 deficiency (odds ratio = 7.32, 95% confidence interval = 2.06–25.99). Conclusion: Diabetes comorbidity is associated with increased risk for vitamin B 6 deficiency in dialysis patients.

Vitamin B6 in Carpal Tunnel Syndrome

Vitamin B6 in Carpal Tunnel Syndrome

The relationship of vitamin B6 status to median nerve function and carpal tunnel syndrome among active industrial workers.

Case reports and small case series suggest that vitamin B6 deficiency is an important etiologic factor in carpal tunnel syndrome (CTS). This hypothesis has never examined in a randomly selected study population, particularly among active workers. We examined 125 randomly selected active workers from two industrial plants. Each worker completed a self-administered symptom questionnaire and underwent electrodiagnostic testing of the median and ulnar sensory nerves. Laboratory biochemical analyses of vitamin B6 status were also performed using the erythrocyte glutamic pyruvic transaminase assay, and quantification of plasma pyridoxal-5'-phosphate. Measurements of vitamin B6 status were unrelated to self-reported symptoms potentially consistent with CTS, electrophysiologically determined median or ulnar nerve function, and CTS defined on the basis of self-reported symptoms and electrophysiologic measurements. These results suggest that CTS among active industrial workers is unrelated to vitamin B6 status. Furthermore, in our opinion, empiric prescription of vitamin B6 to patients with CTS is unwarranted and potentially hazardous.

Zinc, vitamin B-6, and other nutrients in pregnant women attending prenatal clinics in Mexico

Biochemical measurements and 24-h dietary recalls were conducted early (18.9 +/- 5.9 wk) and late (35.1 +/- 2.0 wk) in pregnancy in women attending clinics in Montemorelos, Mexico. Mean weight gain per week (0.4 +/- 0.2 kg) and birth weight (3381 +/- 456 g) were normal. Intakes tended to decline during pregnancy and declined significantly for zinc (p less than 0.05) and vitamin B-6 (p less than 0.03). Mean Zn intake late in pregnancy was low (7.8 +/- 3.3 mg/d). Various supplements were taken but none contained Zn. During pregnancy mean plasma Zn levels fell (p less than 0.001) and late in pregnancy 57% of the women had values suggestive of poor Zn status (less than or equal to 8.1 mumol/L). These data indicate that Zn intakes of approximately 8 mg/d will not maintain plasma Zn levels in late pregnancy. Erythrocyte glutamic-pyruvic transaminase (EGPT) index and the index of diamine oxidase (DAO), a vitamin B-6-requiring enzyme of placental origin, were correlated suggesting that DAO index may be useful in evaluating vitamin B-6 status in pregnancy.

Vitamin B-6 nutriture and plasma diamine oxidase activity in pregnant Hispanic teenagers

Vitamin B-6 status was assessed by measuring erythrocyte glutamic-pyruvic transaminase (EGPT) indices in 122 pregnant Hispanic teenagers. Seventeen percent were vitamin B-6 deficient (EGPT indices > 1.25) at the initial interview (first or second trimester). A daily supplement of 5 mg vitamin B-6, beginning at initial interview, did not reduce prevalence of vitamin B-6 deficiency at final interview (third trimester). No association was found between EGPT indices > 1.25 and the outcome of pregnancy. The activity of diamine oxidase (DAO), a vitamin B-6-dependent enzyme produced by the placental decidua, was measured in maternal plasma. At initial and final interviews, plasma-DAO activity was increased by in vitro addition of pyridoxal-5′-phosphate. The activity in early pregnancy was positively associated with dietary vitamin B-6 intake and was lower in teenagers with EGPT indices > 1.25 at the final interview. Findings suggest that plasma-DAO activity is influenced by vitamin B-6 status.

Daily requirement for pyridoxine supplements in chronic renal failure

Vitamin B6 deficiency was evaluated in 37 patients with chronic renal failure and in 71 patients undergoing maintenance hemodialysis (HD) or intermittent peritoneal dialysis (PD). Vitamin B6 deficiency was assessed by the in vitro activity of erythrocyte glutamic pyruvic transaminase (EGPT), without (basal) and with (stimulated) the addition of pyridoxal-5-phosphate to the assay, and the EGPT index (stimulated activity ./. basal activity). Basal and stimulated EGPT activities were below normal in the HD patients, and the EGPT index was increased in each group of patients, indicating vitamin B6 deficiency. Supplemental pyridoxine hydrochloride was given to 30 HD patients who received 1.25 to 50 mg/day (37 studies), 6 PD patients who were given 1.25 or 2.5 mg/day (7 studies), and 8 nondialyzed patients with mild to severe renal failure who received 2.5 mg/ day. In all HD patients, 10 or 50 mg/day of pyridoxine hydrochloride rapidly corrected the abnormal EGPT index and maintained normal values; with supplements of 5.0 mg/day or less, the index was often abnormal, particularly in those who were septic or taking pyridoxine antagonists. In PD patients and nondialyzed patients with renal failure, 2.5 mg/day of pyridoxine hydrochloride was inadequate to correct rapidly the abnormal index in all patients. These findings suggest that HD patients should receive 10 mg/day of supplemental pyridoxine hydrochloride (8.2 mg/day pyridoxine). PD patients and patients with chronic renal failure should receive about 5.0 mg/day of supplemental pyridoxine hydrochloride (4.1 mg/day pyridoxine). When sepsis intervenes or vitamin B6 antagonists are taken, 10 mg/day of pyridoxine hydrochloride may be a safer supplement for all patients.

Vitamin B6 status of the hospitalized aged

Nutritional status of vitamin B6 was investigated in two groups of 102 hospitalized aged. Vitamin B6 intake was estimated. Erythrocyte glutamic-pyruvic transaminase stimulation in vitro with pyridoxal phosphate and SGOT were studied as the biochemical criteria of vitamin B6 status: 18.6% of the subjects consumed less than 0.66 mg of vitamin B6 per day; 28.4% showed a percentage stimulation in vitro with pyridoxal phosphate of more than 15%. There was no significant correlation between basal erythrocyte glutamic-pyruvic transaminase activity and dietary protein, dietary vitamin B6, dietary vitamin B6/100 g of protein, SGOT, hemoglobin, mean corpuscular volume, and iron. All the biochemical parameters used for evaluating vitamin B6 status appeared higher in females, but no statistical difference between male and female groups was noted. Only SGOT levels of female subjects reflected their vitamin B6 status. A large individual variation of vitamin B6 requirement was indicated in both groups studied. Supplements with 2.5 mg of vitamin B6 to deficient subjects caused an increase in transaminase levels, though females showed a higher response. A higher recommended allowance of vitamin B6 for the aged male and female subjects was considered desirable.

Methionine metabolism and vitamin B6 status in women using oral contraceptives ,

The effect of oral contraceptive agents (OCA) on methionine metabolism and on several other indexes of vitamin B6 status was examined in five women using OCA and four not using these drugs. The subjects collected 24-hr urine specimens on 2 consecutive days. After blood was drawn from the fasting subjects on the morning of day 2, they were given orally 3 g of l-methionine. There were no differences between the two groups either before or after methionine in the excretion of cysteine sulfinic acid and methionine. Although the subjects taking OCA excreted slightly less cystathionine than the controls, the percent increase in the excretion of this metabolite in response to methionine loading was similar in the two groups. Compared to the controls, the subjects using OCA excreted less taurine before and after methionine. Three OCA users had plasma vitamin B6 values (assayed with Saccharomyces uvarum) that were in the normal-low range; two had above average erythrocyte glutamic pyruvic transaminase activity indexes. In both groups erythrocyte glutamic oxaloacetate transaminase values were similar and urinary vitamin B6 tended to parallel vitamin B6 intake. Lower levels of plasma vitamin B6 were observed in the three OCA users whose self-chosen diets supplied two-thirds or less than 2 mg of the vitamin. It is suggested that a marginal intake of vitamin B6 by the OCA users may lower plasma vitamin B6 without increasing the excretion of cystathionine.

Decreased tyrosine transaminase activity in iron deficient rat liver

Iron dependent enzymes were reported to be reduced in iron deficiency (1). Reduction of noniron dependent enzymes, such as glutamic oxaloacetic transaminase, in livers of iron deficient rats were also reported (2). In patients with iron deficiency anaemia, erythrocyte glutamic pyruvic transaminase activity has been shown to be decreased (3). Transaminases may have a special role to assess pyridoxine status, since they require pyridoxal phosphate as coenzyme for their activities. In this communication, we report the tyrosine transaminase ( l-tyrosine:2-oxoglutarate aminotransferase, EC 2.6.1.5) activity has been reduced in iron deficient rat liver and the activity may be restored by adding pyridoxal phosphate in vitro.

Atypical segregation of erythrocyte glutamic-pyruvic transaminase in a Norwegian family. Evidence of a silent allele.

Aberrant segregation of erythrocyte glutamic pyruvic transaminase (GPT) has been encountered in a large Norwegian family. Segregation data are presented. The existence of a silent allele Gpt0, coding

Vitamin B 6 depletion in women using oral contraceptives as determined by erythrocyte glutamic-pyruvic transaminase activities.

To test its effectiveness as an indicator of vitamin-B-6 deficiency erythrocyte glutamic-pyruvic transaminase (EGPT) activity with or without stimulation by pyridoxal phosphate (PALPO) was measured in vitro in a group of 11 control females and 13 females using oral contraceptives. It had been suggested oral contraceptive users may be vitamin-B-6 deficient. Mean basal EGPT activity was significantly lower for contraceptive users (p less than .02) while percentages of stimulation by PALPO were significantly greater than those recorded for the controls (p less than .001). Mean values of EGPT activity with PALPO stimulation were not significantly different between the 2 groups. It is apparent that vitamin-B-6 depletion occurs with use of oral contraceptives and that EGPT with PALPO stimulation is a valid method of determining the vitamin-B-6 status in women using oral contraceptives.

Factors Affecting Vitamin B6 Requirement in the Rat as Determined by Erythrocyte Transaminase Activity

The sensitivity of erythrocyte glutamic-pyruvic transaminase (GPT) activity for assessment of vitamin B6 nutriture was demonstrated by a significant correlation between vitamin intake and GPT activity. The effects of dietary calorie, protein and amino acid intakes on vitamin B6 requirement were investigated in male rats using erythrocyte GPT activity as a criterion of vitamin B6 nutriture. There was no significant difference in erythrocyte GPT activity between hypothalamic-hyperphagic and control rats indicating that an excessive calorie intake does not alter apparent vitamin B6 requirement. With a 40-μg pyridoxine intake daily, there was a decrease in erythrocyte GPT activity as the level of protein in the diet increased, indicating that vitamin B6 requirement is apparently related to the level of dietary protein. Neither amino acid imbalance (8% casein + 15% gelatin) nor methionine toxicity (8% casein + 3% dl-methionine) appeared to alter vitamin B6 requirement as judged by erythrocyte GPT activity.

Vitamin B6 requirement in the hypothalamic-hyperphagic rat.

SummaryControl and hypothalamic-hyperphagic rats were injected daily with pyridoxine hydrochloride at dosage levels of 10, 40, 80, 120, 160, and 200 μg/day for 32 days. Body weights and food intakes were measured throughout the experimental period; erythrocyte glutamic-pyruvic transaminase activities (GPT) were measured at the termination of the experiment. Based on body weight changes, it is suggested that vitamin B6 requirement is in the range 80-120 μg/day for both control and hyperphagic rats. However, a daily dose of at least 200 μg is required to elicit maximum erythrocyte GPT activity. A significant correlation between vitamin intake and enzyme activity was observed thus indicating a direct relationship. There appeared to be no evidence of an increased requirement for vitamin B6 as a consequence of hyperphagia and therefore, it is concluded that in the rat, requirement for this vitamin is not related to calorie intake.

The oral lesions of iron deficiency anaemia: pyridoxine and riboflavin status.

Summary Erythrocyte glutamic pyruvic transaminase activity is reduced in patients with iron deficiency anaemia and can be restored in vitro by the pyridoxal phosphate co‐enzyme. This abnormality is related to the presence of oral epithelial lesions rather than to the degree of anaemia. It is suggested that pyridoxine deficiency may be associated with the occurrence of oral lesions in anaemic patients.