Expressed (highest) in the medial hypothalamic paraventricular nuclei and median eminence by human TRH Gene, 242-aa 27-kDa (precursor) (prepro-)Thyrotropin-Releasing Hormone is a major regulator of TSH biosynthesis and release in the anterior pituitary gland and neurotransmitter/neuromodulator in the central and peripheral nervous systems. (NCI)