Further data on the age-dependent intestinal absorption of dibasic amino acids

Abstract

To study the intestinal absorption of dibasic amino acids (i.e. l-lysine and l-arginine) in rats of different ages, under in vivo conditions, the modified Sheff and Smyth method was used. It has been established that on the basis of kinetic constants ( K M and V max) there were no differences in the lysine and arginine absorption in the (25–26 month) old rat; both are transported similarly, having the analogous K M and V max values. The constants of other cases (cf. arginine absorption in the young and adult rat, lysine absorption in the young animals of 6 months) proved to be perceptibly higher. Unexpected high values were obtained with l-lysine in the 12-month-old (considered as adult) rat. The possible reasons for it are discussed. It is concluded that there are no reasons which would indicate that the absorption of these dibasic amino acids becomas impaired with advancing age.