the N-terminal Gln (glutamine) is converted into pyroglutamate (a cyclic residue). These multiple steps produce 6 copies of the mature TRH molecule per precursor molecule for human TRH (5 for mouse TRH).

TRH synthesizing neurons of the paraventricular nucleus project to the medial portion of the external layer of the median eminence. Following secretion at the median eminence, TRH travels to the anterior pituitary