DIGESTIVE ABSORPTION OF IRON BOUND TO THE 1-25-CASEINOPHOSPHOPEPTIDE OF BETA-CASEIN

Digestive absorption of iron bound to the 1-25 caseinophosphopeptide o f beta-casein. We investigated the digestive absorption of iron using an isolated, perfused rat intestinal loop. Iron bound to the 1-25 case inophosphopeptide of beta-casein (beta-CN (1-25)) was compared to iron gluconate. Half of the animals were bled to induce an acute iron defi ciency, which enhances iron absorption; the protective effect of beta- CN (1-25) against the calcium inhibition of iron absorption was tested as well. In the control or anemic groups, iron disappearance from dig estive lumen was higher in the beta-CN (1-25) than in the gluconate gr oup. In control animals the amount of iron stored was lower in beta-CN (1-25) animals than in animals perfused with gluconate, while both gr oups of anemic animals also displayed lower enterocyte retention than control animals. As a result, the net iron absorption was higher in an imals perfused with beta-CN (1-25) than with gluconate, whether the an imals were iron depleted or not. Addition of calcium to the perfused s olution decreased iron absorption, however, this decrease was signific antly reduced in beta-CN (1-25) groups. The increased solubility of ir on bound to beta-CN (1-25) could explain these results, in association with enhancement of the mucosal transfer of iron taken up by the ente rocyte.