FACTORS AFFECTING THE DISTRIBUTION OF INGESTED PROPIONIC-ACID IN THE RAT FORESTOMACH

Propionic acid (PA) when incorporated into food pellets and fed to mal e Wistar rats for 20 wk had no effect on the forestomach mucosa; howev er, in powdered diet PA led to pronounced hyperplasia and severe infla mmatory lesions in the forestomach mucosa near the limiting ridge. Sin ce this discrepancy in the effect of PA may have been caused by the ty pe of diet in which PA was administered, the distribution of total PA (including the corresponding acid-soluble CoA ester) in different part s of the stomach and certain variables affecting this distribution wer e investigated. In the forestomachs of rats fed 4% PA in powdered diet , the amount of PA in hyperplasias (1553 +/- 508 mug PA/g tissue) was three times higher than that in the remainder of the tissue (479 +/- 2 47 mug PA/g tissue). The PA content decreased progressively towards th e glandular parts. There was a slight, but not significant, decrease i n the PA content of the forestomach and a slight increase in the PA co ntent of the glandular stomach in rats fed pelleted food compared with those fed powdered diet. Supplementation of 1% L-carnitine to PA powd ered diet for 12 wk led to a significant decrease (P < 0.02) in PA acc umulation in hyperplastic tissues compared with hyperplasias induced b y PA alone, although L-carnitine had no influence on the severity of h yperplastic changes in the forestomachs of rats. The present study sho ws that the type of diet in which PA was administered to male Wistar r ats is of great importance for the development of hyperplasia, PA or t he corresponding CoA ester can accumulate in the forestomach and is pr eferably accumulated in hyperplasias, and PA accumulation does not app ear to be directly related to the severity of hyperplastic changes.