Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An attempt was made to determine the effect of steroidal contraceptives on the utilization of Vitamins-B1 and B6. Subjects, aged 22-38 years, were not taking any external source of vitamins. A 24-hour urine sample was collected and a fasting blood sample drawn for the estimation of erythrocyte amino-transferases and transketolase. Then each subject was given 2 gm of L-tryptophan. Another 24-hour urine specimen was then collected. Xanthurenic acid values in urine specimens were compared. Ovral or norgestrel was then given for 3 cycles. After these 3 cycles, blood collections and tryptophan load tests were repeated. Erythrocyte alanine aminotransferase (EAIT) and aspartates aminotransferases (EAsT) were measured. Also, erythrocyte transketolase (ETK) was estimated and the "TPP" effect determined by adding 75 mcg of thiamine pyrophosphate. of 11 women taking Ovral, 7 showed an abnormal response to the tryptophan load as shown by the xanthurenic acid excretion. Responses of all 11 women on norgestrel to tryptophan loads were normal. EAIT and EAsT tests were normal with both drugs (p more than .05). Erythrocyte transketolase activity was not significantly changed by either preparation (p more than .05). The increased xanthurenic acid excretion with Ovral after tryptophan load is thought to indicate Vitamin-B6 deficiency. Basal levels of ETK decreased in 7 of 10 women on Ovral but increased in 5 of 8 women on norgestrel therapy. Also, in vitro stimulation with TPP was observed in 4 of these women. The relation of this finding to Vitamin-B1 is not clear. Urinary thiamine, blood pyruvic acid, and alpha-ketoglutaric acid and transketolase activity require study to assess the Vitamin-B1 status under contraceptive therapy.
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PMID:Short-term effect of ovral and norgestrel on the vitamin B6 and B1 status of women. 119 31

Fed and fasted rats were injected with L-tryptophan (12.5 mg/100 g body weight) and the specific activities of L-glutamic: NAD oxidoreductase (deaminating) (EC 1.4.1.2) (GDH), L-aspartic-2-ketoglutaric aminotransferase (EC 2.6.1.1) (GOT) and L-alanine-2-ketoglutaric aminotransferase (EC 2.6.1.2) (GPT) from hepatic mitochondria and cytosol were compared. L-tryptophan results in a decrease of mitochondrial GDH activity by 22% and of cytosolic GPT and GOT by 42% and 38% respectively in the liver of fasted rats. Xanthurenate is a potent inhibitor of purified extramitochondrial GPT, whereas anthranilate and quinolinate are less potent inhibitors. L-tryptophan, 5-OH-tryptophan and indole exert a slight inhibition. Kynurenine, 5-OH-tryptamine, tryptamine, picolinic acid, nicotinic acid and indoloacetic acid do not show any inhibition of GPT. It is suggested that L-tryptophan injection inhibits extramitochondrial GPT by its transformation to xanthurenate and anthranilate.
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PMID:Effect of L-tryptophan injection in rats on some enzymes of amino acid metabolism in liver. I. In vitro studies of the effect of L-tryptophan and its metabolites on the extramitochondrial L-alanine: 2-ketoglutaric aminotransferase. 722 74