Chromatographic characterization of neuropeptides in post mortem human brain.

Reverse phase high performance liquid chromatography was used to establish the immunoreactive species of five neuropeptides (thyrotropin-releasing hormone, luteinising hormone-releasing hormone, neurotensin, substance-P and somatostatin) in three areas of post mortem human brain--the hypothalamus, amygdala and cortex. In the majority of cases the major immunoreactive peak corresponded to the authentic peptide, although other peaks of immunoreactivity were observed in several instances. It was established that somatostatin-14 was present as the major immunoreactive form and that somatostatin-28 did not occur in any of the three brain areas, although other somatostatin-immunoreactive peaks of unknown structure were detected. In addition to authentic neurotensin in the cortex, a substantial peak of immunoreactivity corresponding to the elution time of neurotensin (1-11) was observed. LH-RH was not detected in the amygdala, but was present in the cortex as a minor component of overall immunoreactivity. The major peak of substance-P immunoreactivity in all three brain areas corresponded to authentic substance-P; in addition immunoreactive material eluting in the region of [Met-O] substance-P, substance-P (5-11) and substance-P (6-11) were detected. TRH occurred as the major peak in all three areas, although minor peaks of immunoreactivity were seen in the amygdala.