Prostaglandin formation in man during intake of different amounts of linoleic acid in formula diets.

Prostaglandin formation in healthy female volunteers was investigated during intake of different amounts of linoleic acid in liquid formula diets (LFD). The average amounts of the metabolites convertible to tetranorprostanedioic acid (TNPDA) were 123 +/- 5.2 (x +/- SEM), 175 +/- 7.0 and 352 +/- 10.8 microgram/day, during 2-week periods with a linoleic acid supply of 0, 4 or 20% of energy, respectively. The day-by-day variations in prostaglandin formation were less than the changes observed due to different amounts of linoleic acid. High linoleic acid intake was followed by an increase of TNPDA in the urine after 3-4 days, which was more pronounced when the linoleic acid intake during the period before had been low. In all persons, the highest amount of TNPDA, 411 +/- 13.2 microgram/day, was found between days 5 and 10 of high linoleic acid intake. From day 11 through day 14 an average of 372 +/- 14.3 microgram/day was found and the values were lower in 5 of 6 persons as compared to the values found between days 5 and 10. At the end of the experiment with LFD providing a linoleic acid supply of 0, 4 or 20% of energy, the percentage of cholesteryl linoleate in plasma increased (35 +/- 1.8, 48 +/- 1.0, 63 +/- 0.6) while those of cholesterylarachidonate decreased (14 +/- 1.0, 10 +/- 0.6, 8 +/- 0.6). During the periods without linoleic acid intake the TNPDA excretion was lowest in all persons. A reduction in linoleic acid supply resulted in a decrease of urinary TNPDA within 1 day.