The regional distribution of neurotensin-like immunoreactivity in central and peripheral tissues of the cat.

The regional distribution of neurotensin-like immunoreactivity (NTLI) was studied by radioimmunoassay in central and peripheral tissues of the cat. In the brain, NTLI showed a wide distribution with highest concentrations in the hypothalamus, the caudate/putamen and the nucleus accumbens. Only low levels of NTLI were measured in the spinal cord and there was no difference between dorsal and ventral horn. In the periphery, NTLI was present in high concentrations in the adrenal medulla and in lower amounts in the superior cervical and the ciliary ganglion. NTLI was present in both lobes of the pituitary gland and throughout the gastrointestinal tract with high concentrations in the ileum. All other peripheral tissues tested contained low but detectable amounts of NTLI. Gel chromatography on Sephadex G-25 was used in order to characterize the immunoreactive material; NTLI in tissue extracts from 3 central and 3 peripheral tissues co-eluted in a single peak at the position of synthetic neurotensin. NTLI is widely distributed throughout cat tissues and there are important differences from the distribution pattern in the rat, the only other species examined in detail to date.