Effect of Age on Gastrointestinal Absorption (Fe, Sr, Pb) in the Rat

Abstract

Gastrointestinal absorption of Fe, Sr, and Pb was studied as a function of age in the rat by means of isotopic labels. Iron-59 absorption was determined by whole body counting, ³⁵Sr and ²¹²Pb absorption by counting gut contents 8 hours after administration of the respective isotopes. Young animals absorb most of the administered dose of all three isotopes. At about the time of weaning absorption abruptly drops to the low level characteristic of the adult. The similarity of the age-absorption curves for Fe, Sr, and Pb suggests that a common maturation process is involved. With respect to Fe, the rate of maturation of the absorptive process can be influenced by the plane of nutrition at those ages when the transition from the infantile to the adult pattern is occurring, but not at earlier or later ages. Cortisone administration has no effect.