Influence of ascorbic acid, sodium citrate, and sodium bicarbonate on the uptake of59Fe-transferrin,54Mn-transferrin, and65Zn-transferrin from lactating mouse mammary gland cells

The effects of ascorbic acid, sodium citrate, and sodium bicarbonate on⁵⁹Fe-transferrin,⁵⁴Mn-transferrin, and⁶⁵Zn-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 the⁵⁹Fe-transferrin uptake is significant and positive.⁵⁴Mn-transferrin and⁶⁵Zn-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.