PROTEIN-KINASE-C ACTIVATION IN RAT COLONIC MUCOSA AFTER DIETS DIFFERING IN THEIR FATTY-ACID COMPOSITION

We studied the effects of different types of dietary fats on fatty aci d composition and activity of protein kinase C (PKC) in rat colonic mu cosa. Activation of PKC, a key enzyme in signal transduction and growt h regulation, provides a mechanism by which dietary components could b e involved in colon carcinogenesis. Male Wistar rats (n = 12/group) we re fed a semisynthetic high fat diet (43% of energy) containing either sunflower oil, rapeseed oil, or butter for 4 weeks ad Libitum. The co ntrol group received a low fat sunflower oil diet (10% of energy). The butter diet increased membrane-associated PKC activity in rat colonic mucosa compared with the low fat control diet (1237 vs. 917 pmol/min per mg prot.; P = 0.028). Mucosal fatty acids reflected dietary fatty acid composition even though there was no clear association between th e amount of mucosal fatty acids and PKC activity. More research is nee ded to elucidate how dietary fatty acids regulate colonic PKC activity . (C) 1997 Elsevier Science Ireland Ltd.