TRH degradation rates vary widely between different animal species

Abstract

A study of the degradation of thyrotropin releasing hormone (TRH) by tissues of a variety of animal species and man has been conducted. Rates of degradation of TRH varied widely between different species and also between different tissues. Except for brain, tissues of dogs appeared devoid of TRH degrading activity. Rates of hydrolysis of TRH by rat plasma were dependent on the animal strain. Constituent amino acids were the major TRH metabolites produced by plasma whereas deamidated TRH was a major product from liver tissues. The cyclic metabolite histidylproline diketopiperazine was not a prominent metabolite in these studies.