Changes in neurotensin-like immunoreactivity during menopausal hot flashes.

An elevation of plasma immunoreactive neurotensin (iNT) was found during menopausal hot flashes. The flash-associated increases in iNT were concomitant with several physiological changes, including increased heart rate, finger blood flow, and finger temperature. Plasma iNT during hot flashes increased 245 +/- 65% (+/- SEM; n = 41), peaking 3.6 +/- 0.4 min after the onset of the hot flash. Immunochemical and chromatographic analyses indicated that the components of iNT elevated during a hot flash consisted primarily of C-terminal-related variants of NT, but not NT itself or any of its known metabolites. The three major substances identified using high pressure liquid chromatography and a C-terminal-directed RIA that appeared in women with hot flashes were also present in plasma of women without hot flashes and men. Since NT is a vasoactive and cardioactive peptide that can also affect temperature regulation, our results suggest the active involvement of these variants of NT in hot flashes.