1. Recent initiatives which advocate an increase in dietary polyunsaturated fat intake have led to the study of the effects of this upon gastrointestinal function.
2. Weanling rats were for 21 weeks fed diets containing 10% fat that were either high or low in polyunsaturated fats. Jejunal function was studied in vitro in an Ussing chamber.
3. Basal intestinal short-circuit was similar in both groups.
4. A decreased EC50 for the non-neural electrogenic secretory responses to acetylcholine, bethanecol and isobutylmethylxanthine was apparent in the jejuna of rats fed a diet high in polyunsaturated fatty acids.
5. Submaximal electrogenic galactose absorption was increased in the rats fed a diet high in polyunsaturated fatty acids.
6. Changing the composition of dietary lipid resulted in a change in the fatty composition of the apical enterocyte membrane.
7. Diets high in polyunsaturated fatty acids may be both prosecretory and proabsorptive in the small intestine.
