Relationship between pyridoxal phosphate and some synthetic oestrogens, gonadotropin and thyroxine in their effects on kynurenine hydrolase and kynurenine aminotransferase enzymes of normal mouse liver.
The interrelationship between pyridoxal phosphate and gonadotropin and thyroxine in their effects on kynurenine metabolism was studied in the whole liver homogenates from male mice. These in vitro studies were planned to investigate the effects of these hormones on the vitamin B6-dependent enzymes, kynurenine aminotransferase and kynurenine hydrolase. It was found that gonadotropin (from serum of pregnant mares) inhibits both enzymes, whereas thyroxine inhibits the kynurenine aminotransaminase enzymes only. There was evidence indicating that pyridoxal phosphate was not the factor directly responsible for the observed inhibition. Increasing concentrations of pyridoxal phosphate were unable to counteract the inhibitory effects of these hormones.
D000818:Animals; D045166:Estradiol Congeners / Q000494:pharmacology*; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006867:Hydrolases / Q000378:metabolism*; D007737:Kynurenine; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D007986:Luteinizing Hormone / Q000494:pharmacology*; D008297:Male; D051379:Mice; D011732:Pyridoxal Phosphate / Q000494:pharmacology*; D013974:Thyroxine / Q000494:pharmacology*; D000637:Transaminases / Q000378:metabolism*
D045166:Estradiol Congeners; D007737:Kynurenine; D011732:Pyridoxal Phosphate; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D000637:Transaminases; D006867:Hydrolases; D013974:Thyroxine