13-cis-retinoic acid alters methionine metabolism in rats.
The effect of dietary 13-cis-retinoic acid (CRA) on hepatic methionine metabolism was examined in young male rats. Rats were fed a 10% casein diet (controls) or this diet supplemented with L-methionine (10 g/kg diet), with or without the addition of CRA (100 mg/kg diet), for 10 d. Methionine-supplemented rats exhibited 7.3- and 1.7-fold greater concentrations of hepatic S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), respectively, relative to controls, which resulted in a 4.9-fold greater SAM:SAH ratio. Likewise, hepatic methionine and taurine concentrations were 6.9- and 4.3-fold greater, respectively, in methionine-supplemented rats than in controls. The addition of CRA to the methionine-supplemented diet prevented the elevations in the hepatic methionine concentration and the SAM:SAH ratio, whereas taurine levels were greater than in methionine-supplemented rats. In rats pretreated with the methionine-supplemented diet, a reduction in the SAM:SAH ratio occurred within 2 d following the addition of CRA to the methionine-supplemented diet. Rats receiving the methionine-supplemented diet exhibited 9.2- and 3.7-fold greater urinary taurine and inorganic sulfate excretions, respectively, relative to controls. Addition of CRA to the methionine-supplemented diet significantly reduced sulfate excretion by 21%. These findings indicate that dietary CRA has the ability to alter the catabolism of methionine and subsequently influence hepatic transmethylation as reflected by the SAM:SAH ratio.
Department of Nutritional Sciences, University of Wisconsin-Madison 53706.
K L
KL
Schalinske
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Steele
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015474:Isotretinoin / Q000008:administration & dosage / Q000494:pharmacology*; D008099:Liver / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism
D013455:Sulfur; D012436:S-Adenosylmethionine; D008715:Methionine; D015474:Isotretinoin