Neurotensin regulation of TSH secretion in the rat.

Tri-iodothyronine stimulates neurotensin secretion from rat hypothalami in vitro. Propylthiouracil treatment of rats is associated with a decrease in anterior pituitary neurotensin content, an increase in hypothalamic content and an impaired release of peptide from hypothalami in vitro. In addition neurotensin has a direct inhibitory effect on TRH-stimulated TSH release from anterior pituitary in vitro. These observations suggest a physiological role for neurotensin in the control of TSH secretion in the rat.