Synthesis of eicosa-2-trans-8,11,14-all cis-tetraenoic acid-3-14C and DL-3-hydroxy eicosa-8,11,14-all cis-trienoic acid-3-14C

A general procedure for the synthesis of 2-trans polyenoic fatty acids and of dl-3-hydroxypolyenoic acids is described. The 2-trans acids are prepared by LiAlH(4) reduction of a suitable polyenoic fatty acid ester to the alcohol, formation of the tosylate, oxidation to the aldehyde, and Doebner condensation of the latter with malonic acid. The 3-hydroxy acids are obtained by reaction of the acyl chloride of a suitable polyenoic acid with the sodium enolate of methyl acetoacetate and sodium methoxide to give the 3-keto ester, the keto group of which is reduced with sodium borohydride to the alcohol. These procedures were applied to the synthesis of eicosa-2-trans-8, 11, 14-all cis-tetraenoic acid-3-(14)C and DL-3-hydroxy eicosa-8, 11, 14-trienoic acid-3-(14)C.     

Turnover of cholesterol-4-14-C and cholic acid-24-14-C by rabbits fed a diet containing lactose

Rabbits fed 0.35% of cholesterol in diets containing either 29.35% of lactose or sucrose were studied for 14 weeks. The rabbits fed lactose had higher plasma and liver cholesterol concentrations than those fed sucrose. The half-life of cholesterol was 19.0 days and 35.0 days for rabbits fed sucrose and lactose, respectively. The half-life, pool size, and daily production of deoxycholic acid were 9.7 days, 1.29 g, and 74.1 mg for rabbits fed sucrose; and 14.2 days, 1.40 g, and 49.1 mg, for those fed lactose. Cholesterol was the major neutral sterol in the feces of the rabbits fed lactose, whereas coprostanol (5 Beta-cholestan-3 Beta-ol) dominated the corresponding fraction in those fed sucrose. The fecal steroid composition did not vary between day and night collections. No sterol esters were detected in the feces. Urinary elimination of radioactivity was less than 10% of that injected. The "lactose effect" seems to be due to enhanced retention of steroids, the mechanism of which has not been elucidated.