Influence of ascorbic acid, sodium citrate, and sodium bicarbonate on the uptake of 59Fe-transferrin, 54Mn-transferrin, and 65Zn-transferrin from lactating mouse mammary gland cells.

The effects of ascorbic acid, sodium citrate, and sodium bicarbonate on 59Fe-transferrin, 54Mn-transferrin, and 65Zn-transferrin uptake by the receptors disposed of plasma membrane isolated from lactating mouse mammary gland cells have been investigated. The effect of 10(-2) mol/L ascorbic acid alone and in combination with NaHCO3 on the 59Fe-transferrin uptake is significant and positive. 54Mn-transferrin and 65Zn-transferrin binding to the cell receptors are influenced optimally by 0.5 mol/L sodium bicarbonate. Sodium citrate alone or in combination with other substances always has a negative effect on binding of these three metals. It is suggested that a precise mechanism may exist with large possibilities to rearrange metal uptake and its transport from blood to milk.