Magnesium Movement in Hypothyroid Sheep 1

Abstract

Summary

We described magnesium transport in hypothyroid and normal sheep with an eight-compartment biomodel fitted by a least-squares technique to data from multiple compartments and routes of entry for ²⁸Mg. Isotopic equilibrium was not attained during this period of observation in hypothyroid or control sheep. Hypothyroidism reduced transfer coefficients for absorption (P < 0.01) of ²⁸Mg from the GI tract but did not change the rate coefficient for endogenous ²⁸Mg losses to feces (P > 0.05). Nutritional balance data indicated higher absorption and retention of Mg in hypothyroid sheep, and the observed decrease in rate of passage of digestive residues suggested that mean retention time of GI tract contents had a definite effect on the availability of Mg.