Conversion of arachidonate to prostanoids by lung microsomes from rats fed varying amounts of vitamin E.
This study was conducted to investigate the effect of dietary vitamin E on prostaglandin (PG) synthesizing activities in the rat lung. Five groups of weanling male rats were fed for 9 wk a vitamin E deficient diet supplemented with 0, 20, 40, 200 and 400 mg-dl-alpha-tocopherol acetate/kg (E0, E20, E40, E200 and E400). Microsomes from lungs of each group were incubated in the presence of [1-14C]-arachidonate. Separation of metabolites was achieved by reversed phase HPLC. Six prostanoids: 6-keto-PGF1 alpha, 6-keto-PGE1, TXB2, PGF2 alpha, PGE2 and PGD2 were eluted isocratically with the solvent system of acetonitrile-water (pH 3.0) (34:66, V/V). Fractions of eluent were collected and the radioactivity of each fraction was determined. The predominant prostanoid synthesized by rat lung microsomes was 6-keto-PGF1 alpha. The specific activity (pmole PG produced/mg protein/min) for the synthesis of 6-keto-PGF1 alpha was 17.6, 29.3, 16.3, 15.3 and 21.2 for the E0, E20, E40, E200 and E400 groups, respectively. Only minor amounts of 6-keto-PGE1, TXB2, PGF2 alpha, PGE2 and PGD2 were synthesized by rat lung microsomes. Although rats fed vitamin E at 20 mg/kg diet showed the highest enzymatic activity for the synthesis of 6-keto-PGF1 alpha, dietary vitamin E had little overall effect on lung microsomal prostanoid biosynthesis.
D000284:Administration, Oral; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D005526:Food, Formulated; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008861:Microsomes / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D013929:Thromboxane B2 / Q000096:biosynthesis; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology*
D001095:Arachidonic Acids; D011453:Prostaglandins; D014810:Vitamin E; D016718:Arachidonic Acid; D013929:Thromboxane B2