COPPER INTESTINAL-ABSORPTION IN THE RAT - EFFECT OF FREE FATTY-ACIDS AND TRIGLYCERIDES

The absorption of some minerals has been shown to be affected by the p resence of unhydrolyzed dietary triglycerides and free fatty acids gen erated from their partial hydrolysis, Since copper (Cu) can form poorl y soluble soaps with long-chain fatty acids, we examined whether the u ptake of Cu from the intestinal lumen is altered by the presence of fa tty acids and triglycerides using an in vivo jejunal perfusion procedu re, Long-chain fatty acids palmitate and stearate at 1.0 mM reduced Cu absorption rates compared with infusates without either fatty acid or triglycerides (means +/- SEM, controls: 104.4 +/- 8.8 pmole/min x cm vs palmitate: 12.5 +/- 17.6, P < 0.01;stearate: 37.2 +/- 25.6, P < 0.0 5). Medium chain free fatty acids had no effect on Cu absorption (capr ylate: 90.6 +/- 14.9, not significant; caproate: 69.5 +/- 14.2, not si gnificant), Similarly, neither an emulsion of medium chain nor long-ch ain triglycerides at a total 1.0 or 2.5 mM concentration altered Cu ab sorption, The inhibitory effect of palmitate and stearate on Cu absorp tion was accompanied by a reduction in lumen-to-mucosa water influx (c ontrols: 5.33 +/- 0.26 mu l/min x cm vs palmitate: 3.20 +/- 0.70, P < 0.01; stearate: 3.36 +/- 0.52, P < 0.01). The data are consistent with a potential impairment of Cu intestinal absorption by long-chain free fatty acids which may accumulate in the jejunum following excessive f at intake and/or lipid malabsorption.