Chromatographic and immunochemical characterization of neurotensin in cat adrenal gland and its release during splanchnic nerve stimulation.

A subpopulation of norepinephrine-containing cells in the cat adrenal medulla contain neurotensin (NT) immunoreactive material. Using high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera we have demonstrated that electrical stimulation of the splanchnic nerve releases NT and its metabolites NT(1-8) and NT(1-12) from cat adrenal gland into the circulation. Blood samples from anesthetized cats were simultaneously collected from the adrenolumbar vein and femoral artery over a 10-min period prior to and during splanchnic nerve stimulation. Trains of stimuli (15 Hz/10V) were applied at 30-s intervals over 10 min. Plasma samples were extracted, run on HPLC and column fractions assayed with C- und N-terminal directed antisera. During splanchnic nerve stimulation unchanged. Concomitant with the increase in NT was a two- to threefold increase in the levels of NT(1-8) and NT(1-12). The chromatographic profiles of extracted adrenal glands showed a major peak of immunoreactive material with the same retention time as NT (18.6 +/- 3.0 pmol/g weight wet of tissue) as well as a small peaks on NT(1-8) (0.96 +/- 0.18 pmol/g) and NT(1-12) (2.05 +/- 0.1 pmol/g). HPLC analysis of a tryptic digest of the NT-like material gave 1.0 equivalent of NT(1-8) and NT(9-13). These results are consistent with the presence of NT in adrenal tissue and its release and metabolism during stimulation of the splanchnic nerve.