Absorption and Gastric Secretion of Iodine-131 and Chlorine-36 in Dairy Calves. ∗

Abstract

Summary

Metabolism of I¹³¹ and Cl³⁶ was investigated by simultaneous daily administration of the two radioisotopes to milk fed dairy calves. Plasma levels of I¹³¹ averaged 1/5 and abomasal I¹³¹ contents 3 times corresponding Cl³⁶ values. Thus, net gastric secretion of iodine exceeded that of chlorine by 15 times. Percentages of daily administered I¹³¹ and Cl³⁶, respectively, excreted during the last 3 days of dosing averaged 15.6 and 12.2% in urine and 31.5 and 0.4% in feces. Chlorine-36 in ingesta from the large intestine was completely water-extractable compared to less than 20% of the I¹³¹ in the same samples.