Effects of vitamins on hepatic nuclear binding of L-tryptophan.
This study investigated the in vitro effects of selected vitamins on nuclear L-tryptophan receptor binding of rat liver. Our results revealed that some fat-soluble vitamins, beta-carotene, retinyl acetate, calciferol, alpha-tocopherol, and Trolox, as well as some water-soluble vitamins, thiamine and riboflavin, acted to inhibit in vitro 3H-tryptophan binding to hepatic nuclei. On the other hand, pyridoxine had little or no effect. The addition of dithiothreitol, a protective agent for sulfhydryl groups, along with each vitamin decreased the vitamin's inhibitory effect on in vitro 3H-tryptophan binding to nuclei, with the exception of riboflavin and calciferol. The addition of L-leucine, which alone had no inhibitory effect on in vitro 3H-tryptophan binding to hepatic nuclei but when added with unlabeled L-tryptophan negated the effect of unlabeled L-tryptophan, caused a markedly diminished inhibitory binding effect due to each of the following vitamins, thiamine, beta-carotene, retinyl acetate, and alpha-tocopherol and Trolox, but no effect on riboflavin and calciferol.
Sidransky
H
H
Department of Pathology, George Washington University Medical Center, Washington, District of Columbia 20037, USA.
Verney
E
E
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D002839:Chromans / Q000378:metabolism / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D004872:Ergocalciferols / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D007930:Leucine / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000378:metabolism; D012256:Riboflavin / Q000378:metabolism / Q000494:pharmacology; D012995:Solubility; D013831:Thiamine / Q000378:metabolism / Q000494:pharmacology; D014364:Tryptophan / Q000378:metabolism*; D014815:Vitamins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
D000975:Antioxidants; D002839:Chromans; D004872:Ergocalciferols; D018160:Receptors, Cytoplasmic and Nuclear; D014815:Vitamins; D014364:Tryptophan; D007930:Leucine; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D004229:Dithiothreitol; D012256:Riboflavin; D013831:Thiamine