Metabolism and Urinary Excretion of Folates in Hypothyroid Rats

Abstract

Hypothyroidism results in decreased urinary excretion of folates leading to enhanced tissue retention of folates. The proportion of polyglutamylfolates, which are better retained by tissues, is elevated in liver, blood, and bone marrow of hypothyroid rats. The hypothyroid condition is discussed in the light of the enhanced proportion of polyglutamylfolate cofactors and increased in vivo oxidation of histidine possibly resulting in under-utilization of one-carbon units of the folate pool leading to a decrease in weight gain.