The inhibition of thyrotropin-releasing hormone deamidation in porcine hypothalamic tissues

Frozen porcine hypothalamic fragments afford an enzymic fraction that forms exclusively pyroGlu-His-Pro by enzymatic degradation of thyroliberin. Ten compounds have been examined as inhibitors of this reaction and the results indicate that the enzyme(s) responsible for this conversion have an absolute sulfhydryl requirement. Concentrations of thyroliberin have also recently been reported in areas of the brain in addition to the hypothalamus. Each of these areas actively degrade thyroliberin with the hypothalamus being most active.