Suppression of hepatic prostaglandin F2 alpha in rats by dietary alpha-tocopherol acetate is independent of total hepatic alpha-tocopherol.
Groups of eight weanling female F344/N rats were fed semipurified diets that supplied 0, 50, 500, 5000, or 15,000 mg alpha-tocopherol acetate/kg diet, with and without 0.05% phenobarbital (PB) for 9 weeks. Both plasma and hepatic alpha-tocopherol levels, measured by HPLC, strongly correlated with alpha-tocopherol intake (r greater than 0.73, p less than 0.0001). Phenobarbital both depleted hepatic alpha-tocopherol and increased plasma alpha-tocopherol significantly. Although treatment with PB for 9 weeks significantly increased GST activity, PB did not affect hepatic prostaglandin (PG)F2 alpha status, as determined by radioimmunoassay. PGF2 alpha was significantly greater (by 52%) in rats fed no alpha-tocopherol than in rats fed 15,000 mg alpha-tocopherol acetate/kg diet. Hepatic PGF2 alpha status was correlated inversely but weakly with dietary alpha-tocopherol (r = -0.24, p less than 0.05). Hepatic PGF2 alpha status was not correlated with hepatic or plasma alpha-tocopherol status. This finding suggests either that there is a small depletion-resistant subcellular alpha-tocopherol pool which regulates PGF2 alpha production or that alpha-tocopherol alters PGF2 alpha production in vivo by an indirect mechanism.
Duitsman
P K
PK
Department of Food Science and Human Nutrition, Iowa State University, Ames 50011.
Chen
H W
HW
Cook
L R
LR
Hendrich
S
S
D000818:Animals; D004032:Diet; D015237:Dinoprost / Q000096:biosynthesis*; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D010634:Phenobarbital / Q000633:toxicity; D051381:Rats; D011916:Rats, Inbred F344; D024505:Tocopherols; D014810:Vitamin E / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D014810:Vitamin E; D015237:Dinoprost; D024502:alpha-Tocopherol; D024505:Tocopherols; D010634:Phenobarbital